Emphasize early testing. Have registration earlier in the semester for the next term. Have open registration for fall semester during the last week in July through the second week in August. Allow no students to register for a class with a prerequisite without test scores. Particularly do not allow these students to register for math and English.
Retention lies with student success.
Do not set them up for failure. Often new faculty are sent to staff advising tables with little or no knowledge of the curriculum or specific courses or where to go for the information. Increase staff to make registration a smooth process for students. Bring in more instructors with 10 month contracts. Give them formal training.