The standing dumbell curl is probably the most common type of
bicep exercise known today. To perform the
exercise, simply grip two equal sized weights in each arm, and allow your arms to extend to 180 degrees, pointed downwards. Standing with feet about shoulder width apart, bring the dumbell up in a straight arc as high as possible, and release slowly. Do not let the weight drop after lifting.
The exercise may be performed either single or double action, however single action is highly recommended. This way, extra concentration and timing can be placed on one muscle for one lift at a time. If the user desires to simulate double action bicep work, using the standing barbell curl provides for better balance when performing the lift.
As with any weight program, a lower weight/higher repitition program works much better at earlier stages. Perhaps it is a bit shameful to see the other people in the gym using 50-60 pound dumbells to your 20, but only time and effort will resolve your issue. Attempting to "keep up" only breaks you in half. Be sure to also observe the weight lifting safety tips.