Agree with the posts above. Unless I'm doing something special, I will usually aim for the center of the published temp range for the yeast you're pitching. Attached is a link if you need to look up your yeast.
Remember, if you have the sensor on the exterior of the fermenter, the actual wort temp will be several degrees warmer. When I first started brewing, I used a water bath to maintain temps. Place the fermenter in a rubbermaid tote and fill half way up with water. Drop in an aquarium heater if you need to add heat, or frozen half liter water bottles if you need to remove heat.