Check who group and who pk often so you know what kind of opposition is out there.

Thieves, assassins and rangers have to come out of hiding every once in awhile. If you see a thief or assassin, you might want to avoid Galadon and the square of Galadon, Tir-talath, voralian city and hamsah as they tend to stalk around here.

Likewise, if you see a ranger that could be hostile, avoid the wilderness areas especially if you are a dwarf, duergar, conjurer or anything that outlanders dislike as many rangers are outlander oriented(not all).

Also, read up on the cabals, races and classes so you know what they are all about, I didn't when I started and until I understood I had a difficult time. At the minimum, know that Scion and Empire, Duergar, Dark elves and Fire giants are evil.

If you play a hiding/stealth class, find out who can see you. Duergar, other thieves, and assassins along with Tribunals can see hidden, I think. Thieves cannot see assassins hiding in the wilderness, but rangers can as long as it isn't plains.

Learn a bit about each class such as aps, necros, thieves, assassins and bards can sleep you. Some classes can deafen you so you can't cast,etc.