When's the best time to negotiate a severance package? Actually, it's when you get hired.

Having provisions spelled out up front in case of a layoff is a negotiation tool often used by upper-level executives. But even if you're not a corner-office hire, there's no reason that you can't ask for a few assurances if worse comes to worst.

When you get a formal job offer, ask for an agreement to be included (e.g., three months' pay in severance, etc.). Should you lose your job, you'll have your contract or offer letter with specific guarantees and possibly legal rights in hand. (Just remember where you filed the sucker!)

If you're already working and have been taking advantage of the Employee of the Month parking spot, then there's usually not much wiggle room on negotiating a better deal -- especially in a mass layoff situation. Most companies consult with a pack of lawyers to make sure the fateful day goes smoothly. While they aren't too fearful of lawsuits, they are concerned about bad press -- both their outside reputation and internally with remaining employees.

Still, there are some measures you can take to soften the layoff blow. Here are a few tips we got from our resident Human Resources Fool:

Get everything you've been promised in writing. It probably will be, anyway. Remember, you cannot be forced to sign something on the spot. Take the paperwork with you and agree to drop it off after you've had time to review it with a cool head. Consult a lawyer if need be -- especially if a lot of money is on the line, or if you were axed before a bonus/commissions/vesting period or some other important deadline. (If you are dismissed "with cause," your former employer may not owe you one red cent.) Then schedule a time to come back with questions and to show off your new tan.

If you have some notice before the day the ax finally falls, do a little research. Call friends who have been through it -- in this economy, chances are a few of your pals can commiserate -- and compare severance package notes. If nothing else, misery loves company.

Volunteer to stay for another 30 or 60 days. If you can set your emotions aside, offer to help with the transition, shutting down your department or training your remaining coworkers. Leaving on good terms is worth it to your employer. And by prolonging full pay and benefits, you can push off your severance for a little while. Added bonus: a glowing reference and the satisfaction of being a bigger person than most.

Consult the employee manual. If you're determined to walk out the door with one of your employer's valuables, take the employee manual. You can glean some important info about policies, procedures, and how long you can hang on to that sweet dental coverage.

For more job-related tips, check the Ask the Headhunter discussion board, where folks chat about everything from negotiating a better salary in a weak economy to avoiding career suicide.