For years I asked myself that question, spending long hours looking into writing scrips and what to put in panels.
I though it would be good to make a thread on discussing how to make comics, wither it's our method or someone else.

What I've come to find out, there is really no right or wrong way to do it, you just got to do what feel right to you.

There are many writing styles to use if you plan on writing scrips to comics. I'm not really good at drawing so I focus more on writing. Some books I would recommend reading, if you can find a copy, is Writers on Comic Scriptwriting vol 1 and 2 link
This book is a collection of interview with comic books writers from Neil Gaiman, Peter David, Brian K Vaughan, Garth Ennis, and many more. they give examples as to how they go about writing the comics we know and love.

I also think you should pick upMaking Comics By Scott McCloud Link
This breaks comic books making down to a science that's easy to understand.
There are other books out there, but those are some I highly recommend