Lenders like to see a consistent job history. They are looking for someone in a position for a longer length of time to assess your ability to pay the mortgage. If you are new at your job, the Lender may want to wait until your probation with the company is over before approving you for a mortgage.
2. Do not make a Major Purchase.
An increse in your debt to income ratio will reduce the amount of monthly income available for your mortgage payment.You may not qualify for that mortgage since you are paying for some other debt. (car,boat,big screen T.V....)