I come across as a fairly competent general at times, and have gotten decnt kill ratios, somtimes losing maybe 500 to 3000 or so. It really depends on who you're facing, the level you're playing on, the terrain, and etc.

Several players have given you tips already, but a reminder is, to get good at something, you do need to practice. I find when I don't play MTW for a while (I rotate the games I play, when my work and wife allow it), I play historical battles and custom battles just to get practice with dealing with troops again.

Another thing I always notice is that baiting tactics often work, hence a reason I like using archer cavs and regular cavs. I often lose quite a few of them (sometimes in the heat of a battle you forget about these guys), but I figure for the havoc they cause and the enemy lines they allow to be broken, it's well worth the casulaities.

Play around with the battles, I love managing the economy too (used to play civ), but fighting the battles is what makes MTW rewarding and memorable. Losing sometimes happens, and sometimes I'll not use the reload button if the battle was close and we both took casualities (I've had battles I've lost where the enemy casuality rate was much higher, a kind of moral victory). You can always reload and replay battles to work on improving your tactics.