This article is designed to be followed simply and easily.
http://www.youtube.com/watch?v=g5B-uz57PJc

1. Team
In any trailer, unless you're going to do one of those pointless flying round spawn ones, you need a team. The bigger the team the better as they probably won't be available all the time as I noticed. Too large increases risk of griefing etc and it is much harder to get everyone to do the right thing.

2. Safety.
Do not underestimate this one. I've had my world ravanged by out of control monsters and players alike. Do not do this on your only world, BACK it UP. Do not give op out to anyone, I know it seems obvious but I can't count the number of times someone has done this.

3. PLAN
Like any project you can't go barging into filming with hope that it will look good. I spent about 1/2 hours alone on the storyline then probably another 2 hours on how it will all look like. Planning is essential but too much can over do it can possibly destroy the creativity.

4. Good Program.
If you want a free one, Ezvid is quite good. For this video I used Camtasia Studio 8, amazing software except in 30 days the demo will run out. Make sure your computer is up to scratch otherwise get someone else to record etc.

5. Editing!
This might be the most important bit of the whole article. Longer is not better, as you see with most official movie trailers, they are short and action packed. If I had a penny for the amount of long walks round spawn and looking at boring buildings, I'd be able to buy my self a cookie! If it's not exciting people won't want to watch and they won't inform their friends. Don't be a cookie, go and make it exciting and interesting, not that cookies aren't exciting and interesting...

6. Music, if the trailer is soundless it feels incomplete, empty, half done. Even if your trailer is complete and utter S*** then at least having music that MATCHES the trailer will make it more bearable to watch. One way of finding good music is typing epic music into you tube and start from there.

7. Don't give up. At times I felt disheartened at progress but it's important to keep going, keep chipping away at it even if it means missing an episode of skins or supernatural. Because to be frank, although some want to help, no one is going to want to do it for you. People help those who help themselves.

I hope this was useful and you enjoyed my trailer (likes and diamonds are welcome!)