What you want to go by is the front shaft,

in spite of the fact that it has a slip joint in it, the

2 yokes on the front shaft should be aligned perfectly with

each other. The rear shaft's 2 yokes will be at 90 degrees

to the 2 yokes on the front shaft(with slip joint between

them).

Look at the rear shaft and you can see that the 2 yokes

are perfectly aligned. (Disregard the rest of the U-joint)

You want the front shaft to be the same way, except that

there is some stuff between the yokes. Since the least

you can be off is one whole spline it is pretty obvious

if it is not right, assuming you know what to look for.

What I do is put the tranny in neutral and turn the

shaft so the yoke on the front is vertical, then put it

in gear, then stab the rear one also vertical. You can

use any position to start but vertical is easy to identify.