Look at the average stats for different values and the stats of your troops. If you are below average more or less across the board, this is near useless cannon fodder (which can be really bad with the morale breaking rules).
As for what's around you - don't count on number at all or getting a full picture of what's there unless you have a spy there (or, since our dominion provides scrying, we have dominion there).
Heavy Cavalry SUCKS. Light Cavalry is not great. Heavy infantry in any numbers sucks. Barbarians - take these out with range. My starting army had hit the 60 barbarians in one of my neighboring starting territories and I might well have lost my starting army.
Archers only hurt low protection units w/o shields (great for killing barbarians though, as long as they have a meat shield in front of them). Shielded and/or high protection units don't fear regular archers too much. Same for slingers. FEAR THE CROSSBOWS!
As a general rule in the first couple turns, assume enemy mages are probably going to suck.
Tribal units/militias - they can hurt in large numbers, but if you have decent troops, and aren't outnumbered too badly, these are you ideal targets.