When it comes to your low credit score, there is no instant fix. Mistakes, old accounts and fraud can come off your credit report quickly. If you have bad credit because of your past financial behavior, it's there to stay for seven years or more.
A major part of your credit score is your credit history. Improving your credit history should be looked at as a process and not an easy button. There are behaviors that are rewarded and behaviors that are penalized. Get to work on the good ones and not only will your credit benefit, your finances will as well.