Consider what age group/population you wish to work with, what kind of methods you would enjoy employing (e.g., art therapy for children and the elderly, EMDR and behavioral therapy for depression and PTSD, or behavioral analysis for people with autism). Graduate school will most likely be a more general program, but some are very specific, and you can always add on additional trainings after you graduate.
Once you pick the type of psychology you'd like to practice, also consider where you want to live in the long run. Balancing these two choices will help you narrow down the programs you find most interesting. Find a mentor in your field, and do not be afraid to email people with questions!