Teach throttle management, establishment of landing glide slope, rudder usage, and standard 3-leg landing approaches.

Don't let them just drive around the sky aimlessly while keeping them out of trouble, and don't let them fall into the habit of only making right or left turns.

My club's field is a ghost town on crosswind days and when the wind is from the non-prevailing direction because a huge number of members only learned enough skills to fly under ideal conditions, got solo'd, then never developed a systematic plan for subsequent skills development. Getting them solo'd isn't the end its the beginning.

Situational awareness is also critical. Far too many people in my club loose airplanes that have flown off into the everglades because they got caught downwind too far out, had no penetration, lost orientation and couldn't make it back. With the light foam things like that T-28 Trojan people are using as trainers this tendency is amplified.