You need to use your brain
This is one of the single best game I've played so far, you get it all, you can buy stuff, such as units or you can spend your money on training your soldiers better.
You also need strategy, if you just send out random units your pretty much screwed, you need to send out the right units at the right time.
And lastly, I like how many races you can choose from, I preferred Demons (kongregate only) mostly cause..well their demons..how cool is that :D
A few complains I have about the game is how expensive some of the stuff is..that makes it kinda hard to get new units and train them and such.
Also the sages take way too long for their bar to charge to send one of them out..makes it pretty much impossible to get them out there, it is good that they take longer then the others, but how long they do take is ridiculous.
My strategy for the same was pretty simple though, when I got to charge, I would bring out sages because of how powerful they are, other then that it was mostly Haberdashers and spear users, depending on what the opposing guys had at the time. Though when you can, like pboxinator said, send out scouts, they really help keep you in the game longer/ help you win even faster because of their speed..never send them in to fight like some of those stupid enemies do hahaha.