Hey.......don't feel bad. We are all right there with you (or at least were at one time).....otherwise we wouldn't be here.
It does take some time but you will see results. You are already headed in the right direction!
When I first started out I had 2 positive TLs from WAY back that were closed and then (I am not kidding) over 30 negatives....my score was in the 400's......I thought I was a hopeless case.. but with the help some great people on a credit forum (which is now gone), I learned A LOT.
The first credit cards that I was able to get were these:
Chevron (rebuilder card), Crown Jewelers (NO credit check - pretty much guaranteed approval as long as you have a job and a phone number), Orchard secured MasterCard, Target and Macy's.
Those are going to be the easiest to get with really low scores. A couple of other things to consider (if you have the cash) is a secure loan through your bank/credit union.......and getting added on as an authorized user on a good friend or family members credit card (good standing with long history).
This is also a good site to look at too...
Who Gave Me Credit....this way you will know (when you apply somewhere) what creditors pull which CRAs......and you can also search by state, score or creditor. It's pretty cool. I always looked through it to decide what card to try and apply for.
And yes.....it's good to dispute and get off the negatives.......but at the same time you want to start building up positive TLs. So go ahead and try applying for one or two of those.
You should DEFINITELY go for Crown Jewelers, there is no credit check and they usually start you out with a $1500 credit limit which will look good on your CRs. Only catch is you have to purchase something before they will report. I bought a very inexpensive pair of earrings and within like a week it was reporting on all 3 CRAs.