[Raymond]

I believe this is very basic, but highly underrated and not emphasized enough:

Start now when are alone, and condition yourself to raise your arm every time you blow your whistle. Either a raised fist (foul) or a raised open hand (for everything else). If you condition yourself to do that it will become second nature and then you can start concentrating on the proper signals, mechanics, and communication that follow every whistle you blow. I see way too many new officials who get so flustered and nervous about blowing the whistle, the rest is not even worth addressing.