I think the most important thing to understand before you really start to dig in with the rebuilding process is that it doesn't happen "quick" as your thread title states. As many will state on this site, credit rebuilding is a marathon not a sprint. It can take 6 months just to start to see results and 1-2 years to get to where you want to be. When you factor negative items into the equation, if you can't get them removed, you're looking at 7 years before you are completely out.
Your scores are in the 600's which are a fine starting point; many start in the 500's so you're already in a better place than many that start the rebuilding process.
The items you are disputing, are you disputing them because they are inaccurate or "just because" and want them gone? Disputes really should only be used if you see something on there that isn't correct.
The biggest thing for you at this point is going to be getting any negative items off of there. If they are legit negatives like the CU loan that went to collections you are going to want to start writing GW letters. Lots of them. Don't stop until you can get the result that you want. There's a thread on the first page in the rebuilding section here called The Saturation Technique which I recommend reading if you decide to start a GW letter campaign.
For the time being, understand that on-time payments and keeping your credit card utilization low make up 2/3 of your cerdit score. If you nail these two categories, your scores will continue to grow. Never miss a payment. Ever. As far as utilization goes, always pay in full. Paying in full is a great habit to get into, especially when you are younger. If you can't afford to buy it in cash, don't put it on your card. Adopting this mentality will work wonders for your credit scores.
Your car payments are very high and this may be something you want to reconsider at some point. $470/mo is a lot which I know you said was your last car loan payment. You didn't mention what the M3 payment will be monthly, but I'd assume it's in the same ballpark which is a big expense to take on for 5, 7 or however many years make up the term of the loan. A lot can happen over those years such as job loss, medical expenses, etc. that could prevent you from being able to keep up. As a result you could fall short in those 2 major categories of on time payments and utilization. You could start missing payments (if you can't afford them) or run up your credit card utilization by channeling other expenses to your card in attempt to have money to make the car payments. Just something to keep in mind as you progress on your credit-rebuilding journey.
If you could provide some additional information about your specific profile, that would be great. Things such as any other negative items you have on your report, age of your oldest account, average age of your accounts (age of all your accounts added up divided by that number of accounts), number of inquiries on your reports, etc. Also I'm pretty sure you suggested that you only have 1 credit card, is that correct?
