You can start by checking your credit report and score. you can visit www.myfreeannualcreditreport or www.karma.com to get a free report, review it and dispute any discrepances with the three different credit bureaus, if you have one. If everything look fine, start shopping for a mortgage broker, they have access to many banks or private lenders with many different options.
Best of Luck,
Maria E. Cipollone