In all my 50+ years of teaching, most of my students begin memorizing their recital piece BEFORE they have even finished learning it. Consequently they memorize only the notes they need to play and they don't learn all the other things such as dynamics, phrasing, pedal, rhythm changes etc.
I already blogged about having the students actually be able to take a blank piece of paper and write out everything in the music (notes, dynamics, phrasing, pedal etc) from memory as a practice strategy. But to know what a song looks like and to know how to play a song are two different things. In playing there are often unusual gaps and poor fingering all of which gives an uneven performance. So a good practice strategy for that is Chaining.
The concept of Chaining comes from Philip Johnston in his book "Practiceopedia." Chaining works from the top down. You actually start by playing at full speed right away. You start by playing a fragment at full speed—just the first two notes of the passage—and then gradually increasing the number of notes in the chain. Once you've got a full speed chain that's four notes long, you'd be looking to extend it to five. The rule is you don't ever extend the chain until you're coping at full speed with the chain you've already got.
What I am noticing with the students is that they are so used to playing fast and then stopping or gapping. It is hard to break an old habit and adopt a newer, better way of doing things. As the students get better at the chaining technique they will start to be able to play 4-5-6-7-and even 8 notes without a gap. Closer to performance time I create a sheet on the wall of the studio. It has each students name and we record at each lesson how many notes (hands together) were played at full speed without a gap.