Just remember you have to keep holding down the mouse button when you take your picture! Other wise it will snap back to the default angle.
Open up your spell book and go to "Options". Then click on "Gameplay Options", and at the bottom set quest helper to off.
Okay this is about all that we can take out of the screenshot without pressing Ctrl+G.
Now when you type in a message the chat log window pops up. Closing this will make things easier.
Pressing "O" instead of manually clicking it closed will make things faster, since the bubble will remain visible for only so long.
When you crop your screenshot make sure that the box isn't touching any of the potion bottles or your spell book. It will be a little akward, but with practice it becomes much easier.
Hope that helps! :)
Okay that's it, I think I've covered everything. If you have any questions feel free to leave a comment!
And remember, "A picture's worth a thousand words." :)