Many people have, so you probably can to. Without knowing what type of issues you have I can't give you specific advice, but in general; pay your bills on time. Keep your credit balances low, pay down any open lines you can. DO NOT close any accounts, that will lower your score. Dispute in writing any errors on your reports to each agency that reports them, TransUnion, Equifax & Experian. Use credit, but don't abuse it. If necessary, get a secured card with your bank or credit union, use it to buy groceries & gas and pay it off monthly.
There are some local lenders who assist with this process and can give you specific advice based on your credit reports. Since you'll need a lender eventually, see if you can find one who can help you. It will go much faster and you'll have a more certain outcome. It will take time regardless, so start immediately.