I learned to reload by reading the Hodgdon manual and carefully following the instructions that came with my Dillon XL650. It's not that hard, but there is no margin for error, so don't try to cut any corners and do exactly what the book says.
It really helps to have a chronograph, just to make sure that you're not doing anything stupid.
=================
I'm going to have to disagree. When reloading typical ammo, rifle or pistol, there is a fairly large margin for error. UNLESS you are loading close to maximum, obviously.
And a chrono is not needed to tell you if you are doing something stupid.
------------------------------
If yer shootin yer pistol and the magazine blows out the bottom and spills ammo all over the ground....
Here's yer sign
If ya look at yer target and ya got oblong holes....
Here's yer sign
If ya load yer gun and the bullit only goes half way into the chamber...
Here's yer sign
If ya pulls the trigger and yer gun goes "plap" instead of "boom"
Here's yer sign
If yer sightin' in yer gun and the target looks like somebody shot it with 00 buck...
Here's yer sign
If ya find unburnt powder particles in yer box of reloads....
Here's yer sign
When ya go home and yer barrel looks like the inside of yer garbage disposal...
Here's yer sign
If ya have to walk more than 3 steps to find yer shell and the primers looks like pancakes....
Here's yer sign