How to evaluate the 5 selection cards
For each of the 5 candidate ranks, ask: how many of the other 4 selection cards build naturally from that foundation, and how many deal to the tableau in a useful position? The rank that maximizes both immediate foundation progress and tableau quality is usually the right choice.
Common mistake
Players often pick the highest or lowest rank out of habit (Ace or King feel 'special') without evaluating the actual position. The selection phase is the only moment of genuine free choice in the game — use it deliberately.