Depends on the nature of the curse, but here's a method I've heard used, simple but fairly powerful and universal.
You will need:
A mirror - preferably full length and that you are able to sit directly in front of.
Elemental candles and/or your usual circle-casting kit
Bowl of water
1. Cast a circle, preferably with the mirror inside it, or right up against one edge, so that it forms the boundary of the circle. Place the bowl of water within the circle, covered by the cloth (There are 1001 ways of casting a circle, so I won't go into it here. Pick one which works for you.)
2. Light candles for the cardinal directions as appropriate.
3. Ground yourself.
4. Look into the mirror, attempting to focus on your aura. If you are not experienced in seeing auras, it might take a while - you're looking for a hazy, rippling effect around your head and body. Try not to focus too hard on seeing it, just let your mind go blank and keep looking into the mirror.
5. Once you have found your aura, look through it, attempting to find any spots, blemishes or marks in it. These would represent the curse on you.
6. Once you have spotted the blemish in your aura, grasp it quickly and firmly with your left hand.
7. Not letting go of the curse, take your athame in your right hand and "untether" the curse from your aura by cutting through the air, as if it were attached to your head by an invisible cord.
8. Place your left hand under the cloth covering the bowl, into the water, and release the curse into the water.
9. Make a short prayer to whichever God(s)/Goddess(es) you revere, asking for their help in binding the curse to the water so you may be rid of it.
10. Dismiss your circle.
11. Tip the contents of the bowl into a fire.
Hope this helps.