Sit in your armchair at home and visualise you are on the flight deck, run through your callouts and point into space at where the appropriate switches would be. You should be able to find any switch or control without thinking about it.
Buy yourself a little notebook, get out your SOP's and write down a step by step guide to a normal flight. This will help you learn what comes next, nobody will mind you referring to these notes during quiet moments in flight.
While you're in the cruise use the same note book to write down info your trainer gives you, and review this when you get home (or to your hotel room) and before your next flight. Not only will this help you remember things that you will quickly forget (due to the amount of information you are trying to absorb whilst being maxed out) but it will also demonstrate that you are making an effort to learn the ropes, I think most trainers will get irritated quickly if they find themselves going over the same old thing after 3-4 flights, especially if its a simple or straightforward task.
From the moment you clock in for your flight, you should have a little voice in your head constantly repeating "What comes next, what comes next, what comes next". If you find yourself doing nothing, then you have ether forgotten to do something or should be reviewing something such as your descent profile, Time/Distance to go, approach and airfield plates, Wx or fuel checks etc.
Forget about how good you thought you were/are, you're only as good as your last flight. If you did bad, go home, be self critical, be constructive, pick yourself up and don't make the same mistakes again.
Every flight is a fresh opportunity to get it right.
Use your training Captains time to good use, if you are sat there not sure what you should be doing or unsure, just ask him something like "What could I do to get ahead?", "Would you do it this way?" or "Im thinking of doing it like this, do you think this is the best way?"
Always be proactive, not reactive.
Know how far you need to descend and slow down in the type of aircraft you are flying.
Dont labour or waste time on irrelevant things. Example, on a Approach/Departure briefing, state the salient points, what you're expecting, what you' re going to do and what you expect the other pilot to do. Dont give a lifestory its boring, people switch off and its an annoying waste of time which you can use to prepare for other things instead.
On the flightdeck, bull**** doesn't baffle brains it just makes you look unprepared. If you dont know something, be honest and question yourself why you didnt know it.
If you make a mistake, put it behind you and talk about it on the ground.
Never give up.