Wheel of Fortune Free Play: Game Show Word Puzzles (Android)
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Various General Tips
Start out by asking for letters S, R, and T early on as they are the most common ones, followed by N, H, D, L, and C.
Goals are like objectives and completing them will get you diamonds. Voting on whether you liked the puzzle or not a certain amount of time is often a part of the daily goal, so it's pretty easy to do.
Save your hints for the bonus round as you can use only one vowel and few consonants in it, so hints can be your saviors, and bonus round is well worth it.
Don't buy the vowels early on, let your opponent do it and spend their own cash, while you keep saving every dollar.