The key features of student achievement were examined at twelve sixth form colleges (SFCs) in the United Kingdom with an emphasis on strategies to maintain and improve performance. It was found that students at SFCs have on average higher prior attainment and suffer less deprivation than their counterparts in General Further Education and Tertiary Colleges. Although SFCs had high levels of student retention, there was concern about low grade point averages. These were among key success factors for SFCs: (1) overall commitment of college administration and staff to student achievement; (2) college-wide strategic planning for review and assessment; (3) intensive student recruitment, placement, and orientation; (4) updated and evolving curriculum and delivery systems; (5) attention to tutorial and other student support services; and 6) rigorous teaching and course review. The study concluded that although SFCs make a major and distinctive contribution to post-16 education, individual institutions vary significantly due to increasingly divergent student populations who have lower levels of prior academic achievement and no family tradition of higher education goals. (There are 23 tables and figures. The bibliography lists 19 references. Appended are a list of colleges that participated in the study and a checklist for consultant visits to colleges). (AJ)