As stated notepad and pencil.
Make a check list the day before , and look back to it when possible/needed.
What i have learned is , when you need or remember something jot it down immediately , because after 5 minutes in stressful conditions you will forget it.
AND ALWAYS ASK THE CHEF OR CERTIFY THAT HE KNOWS WHATS GOING ON.
Communication is key , if you chef has been told or you have asked , then he cant blame you if he or she claims of not knowing or forgeting.
Also always keep your eyes on the time , if you wanna finish something in 15 minutes then finish it in 15 minutes.
Set times for tasks , and anything that needs to be ordered should be done the day before or before prep , thus you always have produce orders written down.
As for the specials , all i can tell you is to speed it up , stay calm , breathe and develop a system to organize your self , have pans hot, water boiling , oven heated , fryers ready , and prep done. Keep everything you need close , and multitask. After a 2-3 weeks of sweating bullets you should see some results.
Ask advice to your chef , after prep ask him/her what he thought of service and what you can do to improve.
Take advantage of slower service hours to benefit you.
Also never do nothing , if your free help others , clean something , prep something anything , never stand around doing nothing .