General Tips and Workarounds

Terraforming & Geology

 * Gnomes getting stuck when digging Holes? Dig "ramps down" instead. The end result will be the same, and your gnomes won't get stuck.
 * You can level large areas by working from the top of a hill or mountain downward. Dig "ramps down" and highlight the entire area you want leveled. Just make sure there are no trees or plants that haven't been cut down or harvested.
 * Gnomes stuck on a single block: This occurs frequently when using the Remove Floor command. Gnomes will mine themselves into a corner and be stuck on a single block. To avoid this, select only the edge blocks of the area, wait until they remove them, then select the next strip. It takes more time, but the reward of not having stuck gnomes is worth it.
 * Not enough flat space under sunlight for farms and pastures? Build a Stairs up, then build a big dirt Floor on the new, higher level (the one the stairs lead to). Your very own dirt island.
 * [GLITCH/EXPLOIT] To "see" caverns, try designating a whole level for mining, the selection box will be red in open spaces. To see Ores, try digging a Stair Down, the selection box is red when it is over ores.
 * Trying to make a moat but there is no water on the map? Make a bunch of 1x1 holes and let them fill up with rainwater. This also works when trying to make a well for an emergency thirst quencher.
 * If you want to remove all that clay from the floor of your mines, a quick way is to designate the entire area as an underground farm. This will cover all dirt floors and leave the clay ones uncovered. Then, you can use replace floor without having to find each square of clay individually.

Gnomes

 * Some foods and drinks are more effective than others (i.e. they will sate the gnomes for longer). Drinks form worst to best are: water, milk, wine/beer/tea. Foods from worst to best are: meat, fruit/egg, bread/sausage, sandwich/omelette. The general rule is the more crafting steps involved, the better it is. (Confirmed by RoboB0b in the forums).

Materials & Hauling

 * Too much dirt hauling going on? Make a 1x1 dirt stockpile in the middle of all the dirt. The gnomes will fill it up with 64 dirt quite fast since it's so near. Then delete the stockpile, and the whole 64 pile of dirt will be moved in one go the main dirt stockpile (meanwhile make sure the main stockpile has lower priority than the 1x1 ones, or is suspended).
 * This is no longer needed after v0.9.15:
 * Gnomes now use items that can be piled (dirt, stone, straw, etc) to pick up similar items while stocking
 * If there is a merchant in the market stall, you can eliminate all dirt, whether is is stockpiled or not, by trading it to the merchant in return for nothing. This also works for raw stone. If you have thousands of raw granite for example, and don't want it, because you have something better, you can give it to the merchants.

Military

 * Enclose all the pastures and farms you have around and pick one spot, which is the entrance. Then put a training-ground right there - no guard station, no patrol routes. Let the squad train on the training-ground. They will automatically stop training when they see an attacker. This way you can have them improve their skills and protect your entrance at the same time.
 * You don't really have to end a patrol-route at the first position to complete it, if you don't want to. You can make them in a straight line, just double-click the last position anywhere. Then leave the 'loop' check-box turned off. They will go back and forth the points like 1-2-3-2-1, which is very useful.
 * If you want your civilians to help your military in defending you kingdom but do not want them to get killed, equip them with a pistol (two if they do not have mining or woodcutting in their profession) instead of a melee weapon. With enough gnomes, they will deal quite a lot of damage and soften the enemies up for your soldiers while remaining relatively safe.

Designations

 * When designating personal quarters for individual gnomes you can avoid hitting the back button all the time just by moving the camera.
 * The value of personal sleeping quarters affects the quality of sleep. Higher value quarters make the gnomes stay awake for longer after sleeping. Dorm rooms are always lower quality than sleeping quarters, and are not affected by value. (Confirmed by RoboB0b in the forums).

Pastures & Animal Husbandry

 * Yak overpopulation. Yaks are prized at the beginning of the game because they will provide food and drink for the first winter. However, they can become a nuisance later on because they multiply faster as their population increases, eventually reaching the point of wandering through all the built areas. The trick to avoid this is to butcher all but one or two of the male yaks once their population is large enough. Keep the males culled, and the population will not get out of hand. Remember that butchering creates body parts and hides as well as meat. Stockpiles need to be created for these or the butcher will run out of room and stop.
 * A carefully structured breeding program can be thrown out of whack by the addition of the offspring to the pasture. Butchering the animal prevents this, but what if you get distracted by a goblin attack, or a particularly valuable ore vein? A useful tactic for keeping your animal populations from suddenly overwhelming you is to build "breeding" pastures, and "butchering" pastures. Limit your primary pasture (your "breeding" pasture) to the exact number of males/females required to keep your animals breeding at the desired rate. Then build secondary (butchering) pastures to contain the resulting offspring. Make sure to have separate secondary pastures for the males and females, or you may end up with two breeding pastures. This way, the new animals will be kept safe in a pasture, without contributing to population growth. Also, if your secondary pastures are large enough, you can delay your butchering until a merchant arrives. This allows you to collect several days worth of milk/eggs/wool from the animals, and gives you the opportunity to sell off the bones/skulls immediately, rather than having to stockpile them.
 * People tend to get carried away when making large pastures of animals. a 6x6 square will handle 3 yaks. a 12x6 sqaure will handle 6, etc. Often you will be just fine with a 12x6 pasture. Expand only when you see a need for it, as overpopulation can lead to a winter apocalypse of your livestock dying.

Hostile Creatures

 * Underground enemies (like golems) spawn in unlit areas near gnomes. According to RoboB0b: "I think it's like they have to be more than 6 tiles away and less than 16 and anywhere between a floor above to 2 floors below. Kingdom worth is ignored here and only the spawn depth is used to determine what kind of enemy to spawn." An underground enemy will spawn on a dark tile at -7 and below after 48 game hours have passed, giving you plenty of time to lay torches to prevent unwanted enemy incursions underground.
 * When any attacking force such as a mant swarm kills any enemy, they will stop for a moment and scatter to wander off. This only applies to enemies that have sighted the victim. On one side, this will cause the attack force to be more disorganized and easier to kill off. However, this also means they will spread across the entire map and endangering future gnomads.
 * Hostiles can still attack enemies one level above or below them. Keep this in mind when building a defensive layout especially ones that involves hatches (they can still attack above even when the hatch is closed).

Construction

 * If there are stockpiles for wood planks and stone blocks, and a workshop is ordered, gnomes will sometimes take the planks and blocks from the project and put them back in the stockpiles. If this happens, use the "Suspend" function to stop it. Right-click the stockpiles and check the Suspend box. Remember to remove the suspension when the project is finished.
 * If two workshop constructions are ordered at once, gnomes may steal each others' planks and blocks instead of getting them from the stockpiles. This can evolve into a situation where gangs of gnomes are running back and forth with the supplies and nothing is being accomplished! The only way to avoid this is to be careful when ordering the projects. Select different woods and blocks for each project. Then the gnomes cannot use each others' supplies and will leave them alone. This problem can also be avoided, by building only one workshop at a time.
 * To increase the efficiency of your workshops, try creating stockpiles of resources that it needs right next to it. For example, you would want to put a stockpile of logs next to a sawmill. It is possible to create a production chain in this fashion.
 * Remember that you do not have to expand horizontally. Unless you are at the edge of the map, it may be more efficient to place your next production zone at the floor below instead of placing one past a currently existing one.

Mechanics

 * Windmills does not have to be on the surface to function; having every tiles above it cleared of floors and walls will suffice. You can tell if the square will allow windmill if there is light shining from above during the day on the underground tile. This is useful for using windmills a few depths below the surface.
 * Try placing axles between your devices, switches, and power source. This allows you to troubleshoot your mechanics system by seeing what axles are powered.
 * When a self-powered trap is triggered, anyone with the mechanics task will rush towards the triggered traps to reset it. Unfortunately, most of the time, the attacking forces will still be alive and will kill your mechanics if they are not well equipped. You can exploit this by having only your military forces have mechanics. Keep in mind that the number of soldiers sent will equal the number of traps triggered. This will not work if your soldiers are on-duty or training, though.

Other

 * Sleepy Gnomes are slower.
 * From observation, it appears that game crashes are related to world size. A small or tiny world seems less prone to crash.