It does get easier... for example, I remember when I first started, just taxiing from where the aircraft was parked to the holding point I didn't have enough mental bandwidth left to properly do the various instrument checks as well as taxi the aircraft, especially if the holding point was close to where the aircraft had been parked.
Now I'm at the stage (next flight should be my cross country qualifier) where I can do the checks and still have enough bandwidth left to monitor the radio. It required training and experience and it still requires concentration.
It's the same in the circuit. How the **** was I supposed to complete a BUMFFICHH check on a downwind leg? There wasn't enough time, never mind get out the "Golf Delta Golf downwind" call! Now I can do it, although if I've done an overhead join and have a short downwind it has to be done quite quickly.
BTW I make a point of rereading the "operational" sections of my Air Law text book every so often, as although it doesn't matter if you can't remember when the ICAO was formed, it does matter that you know the dimensions of an ATZ or which side to overtake on!
--Mik