Yep, I wouldn't bother with handshakes unless either the league rules require them, or you're at a high enough level to be working with neutral assistants and walking the teams out of the changing rooms before KO.
Things you do need to do:
*Arrive early. I usually aim for 45 mins when I'm going somewhere I don't know, maybe cut this down to 30 if I'm sure I know where I'm going, I'm sure the traffic will be good AND I'm sure the pitch will be OK.
*Introduce yourself when you turn up, at least to the home manager/captain, to the away manager as well if you can see someone who fits that description.
*Change. Again, if it's Sunday league and I don't know the pitch, I'd always turn up in kit with an optional tracksuit over the top if it's cold, so only need to change my boots. If you know the pitch and you know they have decent changing rooms, you might might want to just turn up in a tracksuit and change fully.
*Pitch inspection - check for dog mess/rabbit holes around the pitch. Check that the lines are all correct. Check that the goals are stable and that the nets are well fixed to them/the ground, especially at the bottom next to the post. Make sure you do this when the teams can see you at it.
*Warm up - entirely up to you how much of this you want to do, but I'd recommend a small warm up jog and some stretches as an absolute minimum, as it will make you look a bit more professional.
*Kit check - leave this until 10-15 minutes before KO, can be before, after or during your warm up. Approach the teams when they're close together (either doing stretches, doing a team talk or all punting aimless shots at a goal!), ask them to line up/get in a circle and walk around behind them checking boots, wrists/ears for jewellery and socks for tape. Up to you how fussy you want to be regarding the tape, but don't let any jewellery slide.
*Coin toss. 5 mins before KO, walk to the middle with a match ball, blow your whistle to get the captains in, have a chat with them if you want and then do the coin toss. If you have CAR's, brief them here as well.