Scrabble - What if any "House Rules" work to even the playing field with more and less experienced players?
Time limit and patience for the experienced player.

If the experience player limits self to 15 to 30 seconds per play and is very patient with new players, the game levels without house or extensive rule changes.

For new players to get-into-the-game, competition is not needed so much as enjoyment.  For a seasoned competitor, obliging a quick play (and maybe forgoing QI &amp; ZA) is a challenge.  The senior player should not look up words, but tolerate first timer's usage of such.

Other limitations require the senior playing with 5 or 6 or letting others play with 8 or 9.  (I prefer the limits (time, tile count) on the experienced player rather than mess up the fundamentals for the new player.)

See Jolenealaska