Finances. You'll likely be applying for a joint mortgage, so it's time to lay all your cards on the table. Sit down together with a trusted mortgage advisor to determine how much you all qualify to borrow, based on your incomes, credit scores, loans, credit card debt, and any existing mortgages. You'll also need to agree on how the mortgage, shared utilities, and other bills will be paid, such as by opening a joint bank account.

Research mortgage rates. Shop around for the best rates, keeping in mind that a difference of even half a point can translate into significant savings over the loan term. Remember, lenders are often open to negotiation, and it costs nothing to ask if they'll waive or discount certain fees. Also, don't let the fear of costs associated with breaking your current mortgage hold you back from perusing a new one, as in some cases it may be worth paying a one-time penalty now to enjoy a lower interest rate and lower payments moving forward.