Definitely contact a lender who can give you definitive answers on how to get your credit score where you want it to be.
Short of that, just common sense things that will secure a good score would be:
1. Pay your bills on time, never late
2. Whittle down the amounts you owe on credit accounts
3. Do not incur any additional debt until you've achieved your goal
4. If you don't have ANY credit, obtain some sort of credit account and pay it off on time
5. Remain current on any student loans, etc.