Urinary tract infections (uti)

This is first uti I know you can get them from multiple things. Should a woman pee after sex to help prevent a uti again? What else can I do to help prevent one? I am currently on antibiotics for it and the doctor suggest that I start taking cranberry pills after I finish the antibiotics so I will be taking them. This uti has been so painful for being first one and the doctor said that it's usually that he had to change my antibiotics twice now seeing how it was my first one.