Complicated question, I use everything but the half-windsor (because, duh, I'm not a door to door salesman), depending on the thickness of the tie, the occasion, the spread of the collar I'm wearing, and how much I want the knot to stand out.
Here i am building time learning programming and science, and I should've been focused on tying knots. Apparently I should never have quit the Boy Scouts
Relax. I'm just having fun with ya. I'm the network admin at a law firm so wearing one is mandatory Monday-Thursday. It does seem odd wearing a tie in IT, but wearing one *always* works in your favor, especially when dealing with your peers who aren't quite as well dressed. People will always remember if you're dressed better than they are and that lasting impression is what counts.
If your parents cared about you, they would have invested in a good education; a school with a uniform that included a tie and a proud tradition. So sad that they didn't. So sad. I normally tie a full windsor, but I've shifted to thinner ties so the knot isn't as giant as most football players would have. Half windsor is also ok. Mike, there's a website which will teach you how. Practise makes perfect, and a good tie projects confidence, masculinity and testicles.
I learned how to tie a something knot at one point, but I forgot due to disuse. If I wore a tie regularly, I'd probably hang myself with it.
http://www.tie-a-tie.net/ Step-by-step instructions with videos and line drawings for those who don't know or have forgetten how over the years. Bookmark it. You never know when you may need it.