I have the same problem but I find as I move into more deeper sleep that I stop swallowing and it also seems directly related to the amount of attention I give it. A tip I read once was to use more pillows to prop your head up as this can keep you from swallowing. I find that this just makes me pay more attention to it thus making the problem worse tho.

Everyone has different feeling as they enter into dreaming and you may never even get vibrations as I don't get much anything personally. The only feeling I get is tingly sensations and HI. As you try to wild more and more everything will become more usual to you, resulting in you being less excited.

From the only tutorial I've read mentioning eye movement is to minimize it or attempt to stop it completely as this quickens your dream state entry. There should be absolutely no movement when entering the dream state which keeps you attached to the real world. I find that it is very easy to do this if your thinking about something else or not thinking at all. Never had a problem with not scratching itches either tho, everyone is different.

You can achieve a wild in anywhere from 10 seconds to 3 hours or never. I think a good time to either start over or go back to sleep would be 30 mins. Though for the first time you should probably just go until you either fall asleep, wild, or get up hours later to your alarm. For example every time I attempt to wild it takes me about an hour or more. I have only had one wild which took about 30 mins, but the time goes by extremely quickly feeling like mabye 10 mins but my patients always runs thin as I enter paralysis. I'm never giving up though.

Hopefully this information helps.(been reading about lucid dreams everyday since I joined this forum.)