I'll usually watch 3 or 4 pitches from ONE spot. I'll then tell move up 1st baseline and watch his motion for the remainder of his warmup.
I wouldn't immediately think nub if I saw you do all of that. If you do the same routine EVERY time then it just looks like what it is, preparation.
Yeah it's important to look good and all but don't let THAT overwhelm you. Try to be comfortable in yourself. Most Managers have too much crap to do and think about to concern themselves with your lack of experience woes.
What will twig them to your skill level is a visual lack of consistency. Like using the hammer for called strikes all day but missing a few. Looking like a lost tourist between innings or looking at your counter too frequently. If you visualize the count (hold up fingers) do it the same way every time.
WHATever and HOWever you do it....do it the same way EVERY time.
Except for blowing calls!