Rehearse the full capstone talk with slides, applying pacing, eye contact, and volume skills, and incorporate feedback from a practice audience.
Rehearsal means practicing the whole talk out loud, start to finish, with the actual slides, more than once. The first rehearsal is for finding rough spots, and later rehearsals smooth them out.
Time the rehearsal against any time limit for the real talk, and get honest feedback from at least one practice audience member on pace, eye contact, and volume.
Mastery looks like: They rehearse the full capstone talk multiple times with slides, incorporate specific audience feedback, and stay within any time limit.
Common stumbles: Rehearsing silently or only in their head instead of truly out loud; ignoring specific feedback instead of adjusting the next rehearsal.