Pull-ups are one of the very few exercises that look bad-ass.
Not many can do them and make them look effortless.
While pull-ups are certainly easier for lighter folks,those who are built like tanks still should be able to complete at least one pull-up (and even a few more) without gasping for wind.
Being able to have full control over one's body in space is damned impressive. Both girls and guys have the ability to achieve this feat, it just takes a little time.
1) Knee Assisted TRX/Ring Pull-Ups:
Kneel on the floor. Grab the rings so that they are above your head with arms extended. Perform a pull-up onto your toes. (see the above image)
2) Elevated Feet Assisted TRX/Ring Pull-Ups:
Check the image above for the next progression. The box above may be too high, but like a normal pull-up you always want to begin with your torso vertical.
3) Ring Horizontal Rows/Inverted Ring Rows:
While not on the same plain of motion. Performing inverted ring rows allows you the opportunity to build up your relative strength and become accustomed to holding your bodyweight, you also strengthen up the back and biceps.
4) Dead Hangs:
Jump up to a pull-up bar, tree or ledge and hang with the arms straight and the body completely still and in one line. This will help with grip strength and shoulder health.
Work up to holding for 1-2 minutes.
5) Jump Pull-ups Off Step (s)/Box: