I can't stress enough.... call your creditors! Showing a genuine interest in wanting to rebuild your credit should hopefully sway some of them. Obviously this is not a guarantee and if the account is only a few months olds, chances are it's not going to drop. I explained to my creditor that I had opened the account when I was very young and immature when I opened the account and that I was married now and attempting to rebuild my credit, that I've been paying my bills on time for the past 'x' amount of years, and "would you please be willing to work with me to remove this delinquent account from my credit report". I stalled for a long time before calling them simply because I felt weird about doing it and the woman I dealt with was extremely helpful and willing to work with me.
After I opened a CC with Orchard Bank, I waited a while and then opened a JC Penney and Macy's card. I didn't get a high CL, but I still have the cards active and use them once in a while for gifts, etc, but since there is no annual fee, the store cards are very easy to maintain and each month they get reported to the Credit Bureaus as on time.
One of the first cards I had when I was 19 (I'm 30 now) was an AMEX. Of course, I maxed it out and didn't pay it on time, etc. It showed up as a 'paid settlement' on my credit report, which was affecting my score. I called them several years ago and they removed it. Since then, I applied for another AMEX card and it was approved! I carry the following cards:
1 Orchard Bank Master Card - $1800.00 CL ($0.00 balance)
1 Discover Card - $4500.00 CL ($450.00 balance)
1 Chase Platinum Visa - $5000.00 CL ($0.00 balance)
1 AMEX Card - $5000.00 CL ($0.00 balance)
1 STAR Card - $8000.00 CL ($1,550.00 balance)
3 Store Cards (JC Penney, Lord and Taylor, Macys') - $300.00 limit on each ($0.00 balance)
I also took out a small personal loan from my bank that I knew I could pay back. I did this to balance out my credit report. It was for $2500.00. It was a 24 month loan but I paid it off in 12 months.
I also have an auto loan with a remaing balance of about $27,000.
After I pay off my Discover Card, I will charge some minor purchases ($100.00 or so) on my Chase card. The moment I see it pop up on the web site, I will pay it off immediately. Then I will rotate between my other major CCs. Lather, rinse, repeat.
As other posters have said, don't get credit cards then put them in the sock drawer. Use them once in a while to make small purchases then pay them right off. The process takes times but it will definitely help you out in the long run.