Quick answer: A good football prediction site is transparent, accountable and educational. Look for verified tipster records, published reasoning behind each tip, realistic (not guaranteed-win) claims, coverage of the leagues you bet on, clear odds and value context, a responsible-gambling commitment, and free access. Avoid any site selling fixed or guaranteed tips.
The 7 marks of a trustworthy site
Verified records, shown reasoning, honest claims, relevant coverage (including African leagues), value context, responsible gambling, and free useful education.
Red flags to avoid
Guaranteed-win promises, fixed-match sellers, pay-before-results schemes, hidden or edited past results, and pressure to deposit right now.