How do I get better at sneaking?

I've had sneaking increase simply by staying in one place while I waited for enemies to move for me to get a better shot. It seems that you can increase sneaking simply by being crouched near hostile enemies.

You gain sneak xp if you have the flat line and are moving close enough to someone who potentially could see you.

The eye means that you are seen. With or without the text detected. Makes no difference. The line mean you are hidden. The short duration of the text hidden I believe is nothing but a service statement.

What I do to get easy sneak, is completely undress the character (armor and boots makes noise), walk up in a corner behind a sleeping person. And then keep walking into the corner, so that i stay in the same place but is moving while sneaking. The line just has to be flat. No "hidden" necessarry. I get no xp while not moving. Auto-walking in the corner seems to not work this time. Maybe they did not want us to get xp while not in front of the screen.

Go to High Hrothgar, wait for the Graybeards to pray, then crouch behind them and attack. Attack them three times, then switch to another Greybeard. As long as you don't hit them four times in succession, you will not cause them to attack you.