Cursing is easy, in my opinion it is easier than positive magics because negative emotions tend to be so intense. I’m not going to give you an exact spell, but I’ll give you all the basics to create an easily workable hex. These can be used alone or combined as you see fit.
My favorite types of hexes are those involving the burning of items, using poppets, or using personal effects of the person to be cursed. Any kind of personal items can be used; hair, a picture, their signature or any of their handwriting are excellent to use. If you have nothing of the person, and no way to obtain something, simply use your visualization and write their name on a piece of paper. Herbs can be used as well, martial herbs are traditionally used (herbs related to Mars). Some examples include Aloes, Basil, Broomtops, Briony, Cayenne, Cumin, Galangal, Garlic, Gentian, Ginger, Mustard, Nettle, Pepper, Tobacco, and Wormwood.
Remember that you are exerting your will over another person. You must be emotional. Cry if you feel the urge, yell, spit, and cuss over whatever object you are using. Be primal. Don’t waver in your objective, and be clear beforehand what your objective is.
Make sure you have a way to end the curse in mind. Will you burn the object? Bury it? Flush it down the toilet? Make sure it is ready to go and appropriate to your objective. Most importantly, in all this be creative and spontaneous. You must engage your emotions and your passion.