The best way to prepare to purchase a home is to follow the market of where you want to buy and bank some cash! That way you have an understanding of value in the area, and you also have the cash for a nice down payment.
You should also probably contact a mortgage person now to make sure you don't have anything crazy going on with your credit, just so you can feel re-assured that you are good to go. (Sometimes problems can take months to fix)
If you need the name of a good mortgage person contact me, and if you want to sign up for Emailed listings, just go to my website and click "Get Select New Listings by Email"
Thanks and good luck!