For handstands, Roger's article is pretty much what you wanna do. Work up to body facing the wall. If you can get straight... it's pretty much VERY easy to come down. As for body facing the wall, work on your forward rolls and such so you can just roll out of it.
For planches there are multiple ways you can approach this probably the best way is regular strength and then assisted work. For strength, rings pushups, dips, pseudo planche pushups, and really pretty much any type of pressing work you can think of. For holds, put your feet about shoulder level and do lean forwards. In a body facing the wall handstand you can start walking your hands out with your feet on the wall to about planche position and then go back up to handstand. Suprisingly effective.