You will be able to see Datacrons from quite a distance as they emit a large glow around them and shoot a beam of light into the sky. If you are very close to a Datacron you will also be able to hear the sound from them.
Datacron Locations By Planet
Quesh – 3 Datacrons
Green: Endurance +4
Location: 207, 769
Head to the coordinates and look for a pipe with bars. From there you should be able to see your Datacron. There are entrances to each this Datacron on both the north and south sides.
Orange: Cunning +4
Location: 426, -130
Head to the Republic Operation Headquarters. From there head northwest. You will eventually find a fence with a hole in it. Go through the hole, your Datacron is yours!
Red: Strength +4
Location: 558, 1422
This Datacron is simple to get. The coordinates will take you to a hill which is very near the Three Families War Camp. Climb the hill and collect your Datacron!