Well, building your credit IS your first step, and a step in the right direction.
Have you spoken to a mortgage rep yet?
If not, find one, as that's important to do now, so you know what else you need to do to qualify for a loan.
Learn about your mortgage options - become well informed on all aspects of buying a home!
Are you living on a budget? A budget that includes saving money?
You'll need to have a down payment, and also a cushion in the bank, as home ownership costs more than simply making the monthly payments.
You need to have some savings to cover unexpected emergencies and repairs.
You should also connect with a Realtor now - even though your target buying date is a year away.
Learn all you can about the buying process in your area so that when the time comes, you will be prepared and not overwhelmed by the process.
Don't be afraid to ask questions.
Once you have a "team" (lender and agent) working on your behalf, they will be there to walk you through every step of the way.