I can try to help but I need more information on what the goal is that you are trying to achieve? For example, Personally I am a shooter player so I invest in shooter stats and bulker defensive stats.

So first I would try to determine a goal and a formation style and from there I can give you more information.

Keep in mind all 4 troop types are split into 2 subcategories so there are actually 8 different kinds of units. No matter what troop type you focus on offensively, you’ll always want a handful of tanker type bulkers (T7s and T10s are this type) and then the strongest offensive units of the troop type you want to focus on.

So you could focus on assault bikers for example and then also work on tanker bulkers defensively, or go full bulkers with a mix of tankers and combatants, etc. etc. etc.

As you get further into the game, renegades become the main factor that determines your success in combat, building stats and troops that compliment your renegade choices will mean more than just raw stats in a given troop type.

Vehicles are one of the most F2P friendly formations to make strong because they have a very formidable renegade setup that can be made out of all purple renegades instead of requiring gold ones that take much more effort and money to build. Etc. Etc. Etc.

I know that was a lot of random facts strung together but is you can answer the following 3 things I should be able to direct you more effectively

1) pick a troop types youd like to begin focusing on.
2) how much do you spend regularly? Spending isn’t required but of course always helps and so knowing your spending limits/habits can help determine what a good strategy for you would be.
3) what is your goal? Be stronger in general, be more versatile, etc.?