Here's a few snapshots of the "practice runs." You can try a variety of things to get the pattern... I've seen people use tall grass (shown in pic), stencils (also show in a pic) or virtually anything that breaks it up... imagine fanning out a handful of drinking straws.
Basically, I first coat the entire rifle, scope and all, with the base coat. I've found that out of all the practice runs going with a lighter color first as the base tends work best. On the rifle I ended up using the stencil, I held it a few inches away from the rifle and the spray can was a few inches away from that; using a dark brown as my second coat. I found that if you spray too closely to the rifle the lines are too crisp and stand out too much making it look a bit cheesy (you can see this in the zebra like print in the middle pic). But, by holding the can back a bit it made it a softer stripe with more blended edges so the colors look like they belong together. At this point the rifle was pretty 50/50 light tan and dark brown.
The last coat was an OD green. Unfortunately I think I covered too much area and it made the overall look really dark. So I just went over it one last time with the light tan just to "accent" the overall rifle with a few last light stripes.
I must have used 2-3 different stencils/grass, and a few different orders of paint. Tried one that was dark brown, then light tan and OD green. One that was OD green and Black. Overall I liked this combo, but then again the area I shoot tends to have a lot of tall grass, corn, tan brush, etc. So this combo seemed to blend well AND allow me to be pretty adaptable. But find what works for you and then blast the rifle with some paint.
Best part about this is if you mess up, or if it gets scratched, you can easily whip out the stencil and blast a few stripes of paint over it again and cover up any error. Like I said, took me less than an hour including taping it off. I'll take some pics of it tomorrow in the grass and try to load them up