The folks at Fitsugar have excellent instructions on how to deadlift:
- Hold the barbell (or two dumbbells at your sides) close to your legs, almost touching them.
- Keep your arms straight and knees slightly bent.
- Slowly bend at your hip joint -- not your waist -- and lower the weights as far as possible without rounding your back.
- Keep your back straight; a good way to do that is to look forward, rather than at the ground. Keep your spine neutral with a natural low-back arch, shoulders down.
- Squeeze your glutes to pull yourself up at a quicker pace than it took to bend down (Fitsugar recommends four seconds to bend down and two seconds to pull up). Don't use your back. Do not round your spine.
- Using a weight that allows you to do three sets of 12-15 reps, keeping your form strong and correct through to the end.
Be sure to read the article, and not just because it concurs with what I have told clients for years: deadlifts are great for your core, glutes, posture... pretty much every muscle group.