I've been here a year and a half and am only just now starting to get approvals (but still a lot of rejections as well) - I think like Lola said, the 6 months employment thing is a big one, but I also think a bank account for 6 months or more is a biggie - my bank account is still quite new and doesn't have an overdraft and I think that's been an issue.
I agree - getting a bank account is a major plus. If you have one and you can prove to the bank that you have money going in and out and no unauthorised overdrafts then the bank where you account is held will probably be your best bet for a credit card as they take your account performance into account when approving you.
The address problem for bad credit isn't a major issue anymore as it also is looked up on your surname and title.
At the end of the day its the ame old story in that until you get credit you have a bad credit score, so its a catch 22, so the best advice is start slow and within a year of you managing credit with store cards and mailorder you should be OK.
Hope that helps
Steve
P.S. If you goto the experian or Equifax web site you can see your credit file on-line and if some old debt from a previous occupant is present you can apply to have it removed.