I am pretty new to this whole credit repair discussion, in reading may posts I struggled to figure out the abbreviations, until I found a glossary. 
Also, I apologize in advance for the novel!
Alright so down to my situation... I am desperately trying to fix the mistakes of my youth so that I can do things like buy an engagement ring.... I started my credit endeavors with a score in the 700's now I am down to the 500's. After using Credit Karma it shows that 98% of my payments are on time, I am only utilizing 18% of my credit, but I have two negative accounts and 4 inquiries currently.
School Loans
I have a few school loans, one is in a negative status but I am working with the creditor to pay off (going on 3 months now), this loan is around $8,000. But the debt reports twice on my credit file for some reason??? Is there a way to fix this? Also, this went into collections due to the bank stopping the automatic withdrawls from my account when they transfered the loan to another bank. Two others are in good standing and have no negative information on (approximately $8,000 and $6,000 respectively). I have one other loan that is paid off that had gone to collections for the same reason as the first.
Auto Loans
I have one auto loan that hasn't been on their for very long (6 months or so), but in good standing with no lates. My last auto loan showed one or two lates I think.
Credit Cards
Depending on what is showing, I have three open accounts. One isn't showing up, which is a larger amount of open credit $7500 or so. The other two are tiny accounts $100 and $300, both of which are now paid off as well. I have two other credit accounts that are in a credit counseling program (first attempt to help fix the situation). Although they are closed, they report on time payments each month, and lowered my APR to 9.9% on both cards with approximate balances of $3,500 each.
Current Chargeoffs
I have two accounts that are in charge-off status. One of them is a debt to my school for parking tickets. I have talked to the school a hundred times explaining that I sold the car and wasn't even in the same city when the parking charges accrued. But since I had previously registered the car with the campus and the new owner never registered the title, they are refusing to remove the debt. It is only $254, but not my debt. Any way to fight this, or just pay it so it stops killing my credit? I believe this is currently under EOS-CCA, which I read a lot of you have had success getting deletions with. The other account is for a horrible service Events and Adventures that I paid $1,500 into and they say I still owe them another $2700. The service wasn't what was promised and I only went to one event, but the contract I was coaxed into signing does not allow you to cancel and even removed the cooling off period... (should have known, but was young and dumb). This one is housed under Keystone Consulting, anyone ever heard of this?
Inquiries
Of the four inquiries, 2 were for the new auto loan and the other two were current/past creditors rechecking my credit without authorization. I have noticed that a couple of my creditors have taken it upon themselves to occasionally check my credit as well. Is this normal/legal?
My overall debt is roughly 60% of my annual income (including the auto loan, school loans, credit cards, and charg-offs). From some simulators, it looks like the only ways to increase my score now with my current situation is to add a substantial amount of open credit (which is difficult at the moment, since I have very little credit) and to remove the negative accounts. So being a credit repair rookie, if I pay off the negative accounts will it remove the negative accounts?
I guess what it boils down to, is could anyone give me an idea of where to start fixing this mess?