Subj is the best piece of advice and will be given freely by anyone who's been around. Main reasons:

1) Squishiness - dies to anything
2) Hateability - everyone hunts a necro
3) Undesirable groupmate - can't add much (or any) value to the group (unless fairly high-ranked and fairly well-experienced)

To combat that, you need to:

1) Be paranoid and run/word immediately after being attacked. Don't think who or why, just run. If someone finds you, don't think, word. Otherwise you'd be dead five seconds later. Learn to carry word and teleport potions galore. I would also highly suggest fly.

2) Suck up to any higher-level necro to help out with some mage gear. Only do this post-11 and be RP-appropriate in your request. Don't expect much though. If you go caballed, go Empire. They will maybe help you. Then again, a total stranger blade will probably not unless a player's pity bleeds through.

3) Do "who group" early and often - ask anyone who's not obviously good - doesn't matter who, jump at any chance to rank. When grouped, don't annoy people by, for example, scourging the mobs, since your groupmates will catch the scourge and your life will end. Be polite, respectful, responsive. Learn and use all the rescue tricks with your mobs should you grow that far. Reanimate is your friend, use it as much as possible and maybe others will see some value in you and not dump you. Learn to quickly pick up the body pieces and hurl them continuously.

4) If you're new, don't even try to PK before at least having aura and shield (or aura and stone skin). Only exception is you can try to learn how fast you'd be dying by trying a sleep on anyone who has a reasonable chance not to see invis. Don't attempt sleep before mastering it, however. You will die even faster.

5) If you somehow survive to 36 (or whichever level wraithform gives bash prot), stop for a while and really learn the ins and outs of your class. The only reason to rank should be distention. Your goal of 36-47 is to live as long as possible to give yourself a better roll at being undead. If you rush to 47, you won't have con left to attempt.