Here are manuals from the U.S. Marine Corps on how to shoot the rifle and the pistol. The Marines have been thinking carefully about practical shooting since 1775, and have developed some rather definite opinions on how it should be done. The manuals linked here assume use of the M16A2 rifle and the M9 pistol, but the how-to information is adaptable to any rifle or pistol.
The lessons are also adaptable to any use of the rifle or pistol afield, not necessarily in warfare. Being quick, accurate, using a steady position and so on won't hurt your chances if you're just after rabbits with a .22.
The links go to sizable PDF files and may take a while to load.
Happy Independence Day, UK!
1 hour ago