If you are cursed, then it is most likely low-end magick practiced by an amateur. Professionals are generally occupied with more important things. However, amateurs can have a lot of raw power even when their technique is lacking, and their curses can be very dangerous.
There are a couple of ways to deal with a curse. The first one is to become an initiate in some tradition of magick and learn to protect yourself. This is not for everyone (no matter what some of the books may say, not everyone is suited to magick) and is extremely time-consuming, difficult, and brings its own dangers. The second way is to use a simple spell that anyone can do without real training.
Simple Curse-Breaker
Items needed: the target, a tub of water large enough to submerge and wash the target (or enough water to wash down the area if a location), a large quantity of sea salt
Best times: New Moon, a Thursday, noon, midnight, dawn, dusk (any time associated with transitions)
Fill the tub with water. Temperature should be comfortable for a long soak if the target is a living thing.
Open and hold up the container of sea salt.
Clear your mind and say the following words while concentrating on what they mean to you. Say them slowly, confidently, and meditatively: "In the names of my ancestors, my gods, and myself, I call upon thee, oh creatures of Earth and Water. Come forth, cleanse "name of target" of all evil and alien magicks, and restore them (me, it) to balance and health. By our wills combined, so mote it be."
Pour the salt into the water. Use a lot.
Keeping your mind in that calm and meditative state, submerge or wash the target slowly. If you are the target, get in the tub and simply lay back and soak. Relax. Let everything slip away.
Do this for at least ten minutes. When you are done, drain the water away down the drain and rinse it off the target. It is absolutely necessary that all of the saltwater is washed off of the target!
When you are done, say the following in the same way you did step 3: "I thank thee, oh creatures of Earth and Water, in the name of myself, my gods, and my ancestors. Be released to your homes, doing no harm on your way, and return to me with glad hearts when next you are summoned. By our wills combined, so mote it be."
The downside of this is that it is limited in its scope and power and that sometimes it won't be able to defeat a more powerful curse. If this happens, seek a professional to help you, because you won't be able to deal with it without real training.
Conclusion
A curse is serious business, and dealing with them can be scary for a person not used to the world of magick. The good news is that magick is just like any other technology for causing change and its principles can be learned and taken advantage of without becoming an expert. Just like it is possible to diagnose and medicate your own headache without being a doctor, it is possible to apply simple magickal techniques to help you protect yourself and take better control of your life. Good luck!