In the early going, you'll be tempted to build a lot of Farms to fuel your army. Do NOT build too many of them. As you advance, this will become a waste of space and you may demolish several that you spent hours building up.
Food after level 15 or so is something you keep in your backpack, not in your city. While your number one priority is building up your army, and you can start out for the first 7 levels simply following the suggested build path, after that, it is about your castle. The top goal for mid-level players is to get a level 17 castle. This is not easy and takes a lot of dedication, and in the end, you'll accomplish all of the recommended tasks the application gives you.
Look at the castle requirements for the next level, upgrade those buildings (which may require upgrading other buildings) as quickly as you can. Once you reach level 16, you'll have to upgrade almost every building you have.
For resources, spread them out, but don't focus too much on food. One of the key facts is that having 2 level 12 buildings in most cases will be more effective, and take less time, than a level 16 building.
Some of the key buildings you'll want multiples of:
- Infirmary - You will want several of these. You should always have enough room for injured troops! Any troops it cannot hold will die. The higher levels, this is a large investment of time and rss
- Manors - These speed up troop production. Tier 3 troops start out around 16 hours to produce. Once you have manors above level 16, they reduce that time by 1% per level. This seems small, but it adds up
- Barracks - Increases the size of your maximum military. Less important than the above, but still can pay off to have a few
Forthcoming: All building descriptions and values to your city