In the order they were asked:
1. There are hundreds of three-letter words; it's useless to have a list... after you play for a while you just end up knowing them from experience. If the trip set takes an S, it's good... if it takes more than S, it's better. Look through the archives or Top 50 for examples of three-letter trip sets. :-)
2. Obviously it's best to minimize triplicate tiles on the rack. Either GO or GOO would work. The expert way would be to play GO, then GOO in two steps. hehe.
3. Depends on what you're playing for. For most players, yes, you'd want to get rid of one of them, preferably in a two-way set-up or at the very least, just placing it on a colored square. However, if you're a "super-expert" (ahem) and going for Top50-level scores, three premiums on the rack at once would pretty much merit an immediate termination of said game. :)
4. All Q without U words can be found here --http://guitarcosmos.com/scrabble/qnou.html
-= Mike =- |