x-country solo

Scenario: student pilot on x-country solo. About 50hrs.

Planning went fine. One long outbound leg (to satisfy the FARs) and two
shorter inbound legs to fulfill the three landings requirement.

Outbound leg: went great. Course maintained and all visual landmarks
nailed, within a minute of expected time. Landed, got logbook signed, took
off on 1st inbound leg.

First inbound leg was to a class D field close to home (call it ABC); VOR on
field. Dialed in the ABC VOR and looked for visual checkpoints. Instead,
approached another class D field nearby (call it XYZ). Not to make excuses,
but ABC and XYZ actually have some geographic similarities: distance &
direction from towns of about the same size, as well as similar relation to
highways and bodies of water, etc). The visual checkpoints enroute were
also close to each other. However, student ignored two key pieces of
evidence that wrong field was being approached:

--ABC tower reported no radar contact (why student continued approach to XYZ
is therefore unfathomable).
--VOR indicated progressive deviation from course (also not surprising).

Mistake discovered near XYZ pattern (runways obviously didn't match). ABC
tower (still in radio contact) notified. Then XYZ tower contacted, mistake
acknowledged, and profuse apologies offered. (No mention either way of
violation for busting the XYZ class D airspace. Student's main concern is
actually to learn from this error, violation or no).

Trip continued to ABC as planned and on to home. Congratulations offered
for completing x-country solo. No mention of error by student or
instructor.

Suggestions solicited & greatly appreciated...