How do you pose for pictures without feeling awkward? Which pose do you like the most? Why?

The best way to pose for pictures is to not pose. Just go about doing whatever you would normally do. Get a remote to set off the camera if you're shooting yourself, or figure out the time delay settings. Even better, get someone else to shoot you.

Also, don't look into the camera lens.

Of the three samples you have here, the first one is not good, body position wise. Rigid as a mannequin. The second one is better — the position of the feet, touching the doorframe and such — but it's still passive. The third one is better still — love the kick, it has a lot of personality. But your upper body is still rigid and immobile, as is your face.

So, figure out a way to just get shots of you moving about normally, doing whatever it is you want to do, but being active. Animate your face — sing along to a song you like, or tell yourself your favorite joke or whatever. Having other people there with you helps this sort of thing because you'll be interacting with them and that will help you have natural expressions on your face.

Good luck. I hope this helps.