Are these the guardians in the 4 tombs? For three of them I found the best tactic was to stand close to where they appear and immediately attack when they do; for the other I retreated, took out the weaker skeletons first, then attacked the guardian by itself.
Stun helps, though I did not start using it until later. A bow and hit-and-run tactics can be very effective, especially near the beginning of the game. You can also leave Aleroth, and level up a bit on the orcs outside (going south you would start running into tougher orcs, though).
If you drink a shadow potion and use your spin attack near (but not directly on) a creature, you will hit it without turning visible (ie they will stand there taking damage and not counter attack).
Early Starter Tips (NON-Spoiler Version)
