Hi all

Few questions regarding credit cards/credit ratings. These may have come up before but looking for some advice.

I am recent graduate and have just started new job in the city. I'm looking at getting my first credit card to primarily start building a decent credit rating for the future. As a secondary motive however I have been looking at 0% interest cards to enable to me to spread payments for some things for the new flat I have started renting with my gf.

I worry however that I may not be accepted for one of these. I have used the eligibility tool for some of the long ones (e.g Sainsbury's most recent 32month card) and come back with 30% chance of acceptance. I assume a primary reason for this was the mistakes I made regarding my finances during university.
I operated 2 current accounts, one normal and one student. The student account with an interest free overdraft was almost at its limit for the best part of 2 years (and is still very far into that limit) whilst the other account was and always has been in credit. The student account has now transferred into a graduate account giving me 2 years before I start being charged interest. In an attempt to use "free" debt to my advantage, I am currently paying off the overdraft by a minimum every month over 2 years (dividing by 24) to be out of it before being charged interest. My question here is: should I be paying this off sooner to positively impact my credit rating? I can't imagine being overdrawn for another 2 years, despite it being 0%, will do my credit rating any good?

My second question is regarding credit cards. Should I look to get a standard credit card (i.e not 0%) to simply put groceries etc on and pay back on the due date to start improving credit rating? Or would it be worth trying to go for a 0% card? Would both have the same effect of improving my rating? (Or, if I dare to say, would getting 1 of each card be an option?)

Thanks in advance for any help!