Give students feedback on how they did on the project. This can be formal or informal depending on the specific situation.
Rubrics or other assessments can be developed that include assessment of your learning goals and other aspects that are important for your school.
Example from Liger
At Liger, they assess all students using a Liger Exploration (project) Rubric.
They focus on the 3 leadership characteristics, the knowledge they gained, and effort.
They discuss with each student at least once during and after the project is complete.
Students also rate themselves as well on all aspects.
This assessment is given credit and is a major part of their permanent school record.
See Liger's rubric