These are the things to focus on... do not put yourself in debt with a car, there are other better solutions.
1) Get a credit card (Unless you already have one)
-Research this and get the best cash back or points card you can get at the best rate.
- Start with buying gas and groceries every month do not run the balance up.
- Pay the card off every single month. (THIS IS IMPORTANT)
- Never carry a balance above 25% of your credit limit.
- Every 8 months or so call your credit card company and ask for a credit line increase. They should be able to do this WITHOUT pulling your credit you are only looking for the automatic increment that they can automatically approve. This will help increase your available credit and will help keep your credit utilization low. Only do this is you are successfully doing the other bullet points above.
2) Pay all of your bills on time, this includes everything from water, electricity, phone bill, etc. never be late. Setup automatic payments if you can.
3) Minimize the number of hard credit inquiries.
-This is particularly important when you are looking for your mortgage lender. Do not let them pull your credit automatically. You should be able to provide them your credit score and other information and get quotes from those lenders. Do not let them tell you then can't do this... they can.
4)Strategically plan when you close a credit line, closing them will do two things, lower your credit limit often times increasing your credit utilization, and it may hurt your average age of credit. Open one credit card and keep it forever.
*Note: Credit Karma is a great tool, you should check your score monthly and see how your efforts are influencing your score. I also like Citi credit cards because they will provide you monthly with your FICO Score which Credit Karma will only provide TransUnion and Equifax.
This is educational information and you should consider talking to a banker/lender who can also give you more detailed instructions on how to get your credit improved so that they can approve you for a loan.
Many people can get their score above 720 in 1-2 years time going from no credit doing the steps described above. It does take time be patient and don't fall for gimmicks.