Поставить в вопросительную и отрицательную форму.
I sleep every day.
I slept yesterday.
I will sleep tomorrow.

I sleep every day
--I am sleep not every day
-Am sleep every day
I slept yesterday
-Am slept yesterday
--I am slept  NOT yesterday
I will sleep tommorow
--I am sleep not tommorow
-Am will sleep tommorow

I dont sleep 
Do i sleep 
I didnt sleep 
Did i sleep
I wont sleep
Wont i sleep