I'm new to this game (one week and level 21). At around level 8 I learnt splitting arrows which gave me a leg up. Now I'm in love with my bow, although elemental arrows is a better spell. I've got a hunter bow and drop heavy orcs in 2 or 3 hits (no mana used).
Another tactic I like is to summon a wall of steel warriors and then use freeze on an enemy or 2 (3rd level freeze now), meanwhile I'm in the back plugging the poor frozen chump with arrows. Works pretty well on orc ellites. <img src="/ubbthreads/images/graemlins/winkwink.gif" alt="" />