You can boost your new salary by making a couple of smart choices on the first day. Start by enrolling in the 401(k). The average company these days will match 50 percent of your contributions up to 6 percent of your salary. That's $1,200 a year for someone with an annual salary of $40,000—free money you'll leave on the table if you choose not to contribute. If your company offers it (many do), open a flexible spending account that you can use to pay for up to $10,000 in healthcare and child or eldercare expenses. Because you deposit pretax dollars, you'll save one-quarter to one-third of the cost on things like braces, over-the-counter medicines and daycare.

Deduct your job-hunting expenses. If you itemize on your taxes, remember that job-hunting expenses can be deducted. This is a deduction, not a credit. But it can include the cost of outplacement or headhunting services, travel expenses if you traveled to an interview and mileage added to your car as you drove around looking for a job. Potential savings: $100 or $200.