Those links are all you need. I used ideas from them to do my own and I can barely thread a needle without hurting myself. Takes rather little time and is actually very easy to do. Yesterday I picked up a few more jackets to convert, including a tux jacket to turn into something formal. If I can do it, anybody can do it.

Biggest tip that I can think of is, when you think you have everything measured, marked and pinned, check it over at least two times, then give yourself extra material on folds to correct any small errors. Nothing is permanent unless you cut it.