Listen to the piece of music you will perform. Having a firm sense of how the piece sounds can help you to memorize the sheet music more effectively.
Play the piece frequently. Frequent practice helps to embed music into the memory.
Break the piece down into smaller sections. Look at the smaller section on the sheet music and play it. Then try to play it from memory. Repeat this until you can successfully play that section from memory multiple times. Move to the next section. Revisit previous sections as you learn new ones in order to keep them fresh in your memory.
Simulate playing the piece of sheet music without your instrument. Go through the physical motions of playing the piece without actually playing it.
Highlight sections of the sheet music with markers of different colors. This visual aid can help you recall specific sections.
Repeat sections in which you make a mistake when playing from memory. If you play a section correctly after messing up several times, you are more likely to remember it in the future.
Write a rough copy of the sheet music from memory to ensure that you are remembering it correctly. Check it against the original.