I guess all the things I have to say are going to sound really confusing after what every one else just said, but here goes.
First off, what I think is more important than 'always mark your holes' is to
NEVER mark your stitch holes!
If you mark the holes then you don't learn the fine art of needle control and stitch placement.
When you make a bag you cut out panels in whatever dimensions you feel like working with, then decide upon a few parameters that you have to keep completely constant on every edge. These basic parameters include stitch depth (from the edge), number of holes per edge and amount of gather. Gather refers to how much you 'bunch up' the edges after they've been stitched, this is either done after stitching the full perimeter of a pentagon or after each edge.
The degree that you gather it, from not at all to completely gathered, will affect many characteristics of the bag. In general, a less gathered bag will feel looser and more supple earlier in the break in process. But this is only in general, some masters of the needle stitch quite tight but still produce delectable soft bags, it's
all in technique!
So, on the topic of actually getting into making bags I guess the question is how much stitching experience do you have?
You said you can tackle any crafty thing, so this is right up your alley.
My suggestion to every new stitcher is to start out on a 4 panel bag. They are the easiest to put together and a great way to get used to dealing with panels, a needle and thread in your hands. It is a very fine and precise thing mostly, and it really just boils down to consistency and being able to repeat a stitch perfectly for the whole of the bag.
Here is an image containing the shape you would need to make a 4 panel.
Print that out and then use it to trace some panel shapes onto some microfleece or crushed panne and then make a whole bunch of panels to practice with.
To make the 4 panel you just put 2 pieces face to face then do a running stitch down an edge at about 1/4 inch depth, add a panel when you get to the tip and continue to the end. Use a length of thread (I use exclusively waxed dental floss from the dollar store) a bit more than arms length.
Hahahah I just now realized I am basically explaining all of everything ever. I really need dinner.
So all I should have said was:
- don't mark your stitch spots, just learn to use your eyes and magical powers
- start with a few 4 panels to learn to handle small panels and stitching
- when making a 32 (or any bag) it is ALL about consistency to make a sphere
- practice makes you better