having inf attack only veh and veh only attacking tanks or should i just have both of my inf and veh squads be able to attack any of the 3.

step1 nly have 1 chassis
(inf/veh/tank)
step2: only use range and armor, ratios vary with the player tho generaly they are a 3:1 or a 4:1 ratio range : armor

thats the backbone of a good army
as for what weapon you need, that really depends on who you are gunna be fighting, specialise if needed, balence is always good, but also taking advantage of a chassis`bonus can be great

i like my army all one chassis though there is a lot of controversy about whether one type is better then a mix

i use a 3:1 range to armor ration ( i think its 3:1...)
so if you use inf it would be
21 range and 9 armor

and i think a good army is a balanced army is a good one... and it also depends on what your against too like zudamar said

The best army is debated alot. As they both said, pick one chassis to use and only build range and armor. The most common builds are:

Inf: 21/0/9
Cav/Vec: 10/0/5
Hev/Mech: 7/0/3

Personally, I use Vec with a ratio of 11/0/4. When i'm in a top alliance that gets in wars, we always make our armor slashing so that we have balanced gains and losses.

The answer is simple; the best army is the one that works for you.

Army compositions should depend on what you need to get done. But of course, the basics would be ranged/armour ratios (already explained) and sticking to one type of chassis as best as possible.

Also, I find that most people, even some in top alliances, tend to use tanks, so always have a good supply of anti-tank vechs on hand.

one last question does inf have bonuses attacking veh and does veh have bonuses attacking tanks if you would please answer this i will be building a army that is best for me.

Yes and yes.Tanks have no bonus

Not necessarily true. While it's true tanks have no technical bonus, they make up for it by increased firepower and hit points (per unit basis). I always count that as a bonus.