Rebuilding your credit rating will not happen overnight.
In the first place it takes from 7 to 10 years for any negative remarks to be removed from your credit report and your credit rating cannot really fully improve without those negative remarks being removed from your credit rating.
But overtime if you have current loans or credit cards that you have been making on time payments for then those on time payments should start to slowly improve your credit rating.
You should start to see your credit rating improve by a little bit within a year of making on time payments but it can take up to 5 to 7 years and in some cases 10 years for your credit rating to really climb to the highest and best credit rating as long as you don't default on any loans or credit card payments.