As far as armies go... There are a few different types of armies you can use.
Catapult/Infantry armies
Archers are great to get started, but really, you dont want to rely on them, they have major damage detriments vs the very cheap infantry (30% damage loss) and whenever troops reach their lines, they take an additional 20% damage loss.
Infantry are basically your fodder for ranged armies. Meat shields and carrying capacity. with an overload of 80, they are the best overload for resources spent and crop consumption. You dont want to throw them away in a battle, but if somethings going to get to your archers or catapults, you will need them to keep those damage dealers safe. They are also great for walking through traps.
Catapults hit very hard and have high range. The downside is they are VEEEEERY slow. When checking travel time on the map for an attack, with catapults, you have to multiply that by 3x. That is to say if it takes infantry 1 hour to get there, the attack will take catapults three hours. The only way to reduce that is to level up your speed and marching (these two are the most important stats/techs to max out, as speed will determine who attacks first in a round. higher speed attacks first, if the speed is even, the defender attacks first. There is no use in hitting hard if you are only hitting with "whatever is left") The objective of a catapult army is to stay far enough out of range that you can kill all of the troops without losing any catapults. Higher range tech will allow you to shoot further, this combined with a higher speed will drastically reduce your losses in battle.
Another tactic is to use a Cavalry army. Cavalry are the fastest units in the game, and if an attack is timed properly, you can take out your enemy's catapults without losing a unit. This tactic it is imperative that you maximize speed and marching as early as possible. once your speed is maxed, you will want to turn to defense. Equippables are important here, as increasing speed and defense will enhance your battle ability. This is not recommended for new/low level players.
Do not build everything. Stick with cats/inf or cavs/inf (perhaps with a bit of cat backup). building all troops will leave you with high crop consumption demands and an underpowered army.
Some guides can be found here:
viewtopic.php?f=59&t=2683Finally, and most importantly
ALWAYS SEND YOUR TROOPS HUNTING!
There will always be higher levels, or people gunning for you. Hiding your troops in hint will protect them for the most part. However if your troops starve, they will return from their hunt.
Happy hunting.