You may not think about strengthening your hip muscles until they start to bother you, but please reconsider!
This is especially the case if you sit all day. Counteracting that with hip-targeting movements will be very beneficial.
Directions:
Lie on your left side, with your left leg straight, right leg straight, and right foot resting on the ground.
Lift your right leg up, maintaining the position of your body. Make sure your hips don’t open up.
Return to the start position. Repeat for the desired number of reps, then do the other side.