List building guidance

So im looking into building some lists, honestly having fun learning the games ins and outs and really like shadow collective even if it needs a lot of work and like a lot of the options the seperatists have. to be honest everything looks so cool except rebels, visually just not my thing. So when trying to make a list what do you try do in most lists you do, do you always try to include something movement 3? try to always have a force user or something.

Can think of somethings that might be useful like a speeder, or a sniper of some sort or some heavy armour incase the enemy underprepares for a tank.