kojunho, a lot of that conduit I did on the ground, and just passed up to someone else to hang. (I just get one measurement) Essentially, they are all the same bend with 2" (Or any other spacing...) added in one way or another. (To the kick, or length of stub) Believe it or not, it is pretty easy once you get the hang of it.
Concentrics, like these by kdal are a lot more tricky.
But there are a few books with the formulas and techniques laid out fairly well. After that, it is just practice. And that takes time, and the opprotunity.
Pipe is one skill that is both required and enjoyable in all areas of the trade. Resi, Comm, Ind, something that anyone calling themselves an Electrician should have mastered. Essentially all of the skills are the same in each, just the materials vary IMO.
The other day, I did a 200a service in 2" RMC through a 2X4, and a 2X6 wall, with 210 degrees of bend with all threaded connections. (30-rolling-OS to meter, and back to back 90's to the main in the next stud bay. No threadless or 3-piece couplings.) The only reason I had to go do it, is that there are some nay sayers on my crew, who said it could not be done.