The first thing we should look at is your chosen troop type. At first it is preferable to choose just one type to specialise in for your army. This is because it can become very expensive and non efficient for you to upgrade many types at once. If you do decide to do two troop types then a good second one to consider is scouts. Some people chose scouts as a first troop which means they restrict themselves in the game to the limitations of a scouts level of participation in some of the mechanics. It is a very different game to other players if you decide to have scouts as your main troop. All other troop types from scouts have similar battle mechanics and just have slightly different attributes to each other.