Before asking for a raise, notice how well your department and company is doing. Is your manager complaining about cutbacks? Right timing is essential. Don't suggest a raise when business is down.
Prepare a statement of major accomplishments. List your results, achievements, and home runs. Give specific examples with percentages, numbers, facts, and figures. Make before-and-after comparisons. Write your goals for next quarter. Rather than explaining your need for a raise as a personal issue--for example, "My husband lost his job"-- present it in a business framework. Explain how others with similar responsibilities are paid. Show industry research and show your accomplishments and goals.
Never present your request for a raise as a demand or threat. That makes you an adversary. Instead, take a questioning approach supported with written facts. You could say: "I've accomplished more than expected (show accomplishments), and I plan to do even more next quarter (show goals). How do you think the company would feel about paying me X-dollars per month (indicating the raise)? That's what others in similar positions are making these days (show market research).
Last of all, wait until your manager is on a personal high, and don't expect a decision overnight. Give the boss your ideas, then give him or her time to think. Chances are, if you've been producing more than expected, your manager can justify a raise.