When shopping for a mortgage, it's essential to prepare your finances by reviewing your credit score, calculating your debt-to-income ratio, and assessing your savings for upfront costs. Determine how much you can afford, including down payments and ongoing expenses. Get prequalified to estimate potential loan amounts, research various loan options, and apply for preapproval to strengthen your buying position. Compare loan estimates from different lenders to find the best terms, and consider locking in your interest rate to avoid fluctuations before closing.