1. Start with a spending plan
Decide upfront how much you'll spend on your vacation. Get specific.
Along with plane tickets (or gas, if you're driving) and hotel prices, guesstimate costs for meals, souvenirs, and park or museum admissions. Total it all up. If the number sends you into shock, cut back on costs -- now, on paper -- until you feel comfortable with what you're spending. If money is really tight, consider a couple of long weekend trips instead of one "dream" vacation this summer.
2. Sacrifice now for fun later
Do you belong to a health club or subscribe to a service (such as cable or satellite TV, a cell phone plan, etc.) that you no longer use, or could easily downgrade?
"Drop the service now and stash the money away for your family's summer vacation," says Kim Danger, founder of Mommysavers.com. Also consider cutting back for a few months on nonessentials like kids' dance lessons, your weekly Pilates classes, your husband's trips to the batting cage or your family's monthly movie-rental service.
Remember: You're just trading today's fun for the fun you'll have during your vacation. Move what you normally would have spent on these items into your vacation fund. Ideally, that would be a special savings account or an easy-to-track category within your larger savings account.
3. Build cash with a 'Pantry Week'
For one week each month, from now until your trip, stay out of the grocery store and eat only what you have in your house. Mary Hunt, founder and editor of Debtproofliving.com and author of "Live Your Life for Half the Price," calls this quick money-raising challenge the "Pantry Week."
Make it fun by pretending you're on a deserted island and can only eat what you have in the pantry. What unusual meals can the kids suggest? "Most families have more staples in their cupboards than they realize," says Hunt. And guess what? It's actually OK to eat peanut butter and jelly for dinner one night.
4. Eat out less, save big
A typical family with kids younger than age 6 spends an average of $239 each month on restaurant meals, according to the National Restaurant Association. That's money that could easily be diverted to your vacation fund.
Some ways to cut back without going cold turkey: Check local restaurants for "kids eat free" nights (often Monday or Tuesday nights), watch newspaper coupon inserts for buy one entree, get one free dining deals or buy discounted coupons (usually $25 certificates for $10) at Restaurant.com.
Frozen dinners or ready-made grocery deli items are much cheaper than restaurant food if all you really need is a cooking break. You could also eat dinner inexpensively at home, then treat the family to a modest dessert out.