Are you having problems with the layout or the stitching method?
The layout!, and I am an experienced crocheted!
I copied the layout "ambivalent" posted during the week of "guess what it is going to look like," but any would do and there are tons of new layouts on the "finished blanket forum" now. I tried multiple layouts on a double bed until I settled on Ambivalent's.
After I got it the way I wanted, I used short pieces of of yarn to tie the pieces together at the corners. Some people use safety pins but I have had a problem with them getting caught in the yarn. I tied at the corners so it was not difficult to locate them later. I moved the "tied-together" afghan to the diningroom table, rolled one side of it so I could work on seaming the other side; as the seaming progressed, I rolled the seamed side also and worked in the middle. I cannot do something like this on my lap.
I used the method of seaming from the Bernat 2010 CAL and it really doesn't show. If I had it to do again, I would probably just use my main color and not try to match yarn colors to what I was seaming since it does not show.
I am not sure if this is going to help you any but hope so. Good luck and post again if I might be of any more help.