Pay $100 extra on your mortgage principle each month – be sure that you designate the payment goes towards the principle.
Buy the smallest and least expensive house that you can and make sure that your payments are only 25% of half your income (or 25% of one spouse’s income). If your circumstances change in the future then you will still have a payment you can afford.
Borrow for the shortest term you can - get your mortgage for 10 years or 15 years instead of the typical 30 years. The payments may be higher but you will be out of debt before your children start having children.