Ask friends, family and co-workers if they have purchased and who they used. It is important that you find someone who is patient in the first-time home buying process. Then insist that you get pre-approved. This will leave nothing to chance and prevent you from having to go through much grief which often happens just prior to closing.
When shopping for a mortgage company or bank, make sure you do it during a two week period. If you extend beyond that time period, such as credit checks, it may affect your credit rating.
Good credit and debt to income ratio is key in buying or renting these days. Once you have been approved for either, do not make any late payments and do not make any big purchases.
If you find, after meeting with the first lender, that your credit scores are not so favorable, he/she will be able to advise you as to how to go forward. I have seen credit scores repaired in as little as six months. Of course, this greatly depends on the score and they type of credit issues that exist.
Hope this was helpful.