2. They think the best play is the one that scores the most points
There's a big difference between a good play and a high-scoring play.
In many cases, a play may score a ton of points, but has hidden drawbacks — for example, it could leave you with nothing but consonants or nothing but vowels, which will hamper your ability to score on your next turn.
Alternatively, your high-scoring play could open up an even more high-scoring spot on the board for your opponent to use, like if you play a word right next to a triple-word score. What's the point of scoring 35 points if it allows your opponent to easily score 40?
When you're deciding multiple words to play, consider not only how much they score, but how they affect both your ability to score on future turns and your opponent's ability to score right back. Defense is just as important as offense in Scrabble, and the best move isn't always the highest-scoring one. It's simply the one that gives you the best chance of winning.
3. They waste the two best tiles in the game
The two best tiles in Scrabble are the S and the blank.
The S is valuable because you can tack it on to the end of most nouns and verbs. That can turn your six-letter word into a seven-letter word, earning you a 50-point "bingo" bonus. The S also allows you to hook your high-scoring word onto an existing word on the board, like in the example above.
The blank, meanwhile, can be used as any letter you want.
There are only four S's and two blanks in the game, and because they are so rare, they should only be reserved for especially high-scoring plays. One rule of thumb holds that you shouldn't use your S unless it scores at least eight more points than your next highest-scoring play, and you shouldn't use the blank unless it scores at least 25 points more than your next highest-scoring play.
4. They hold on to the Q way too long
The Q is the most dreaded tile in Scrabble — it appears in relatively few words, usually needs to be paired with a U to be effective, and it drastically reduces your odds of making a high-scoring play.
That's why one of the biggest mistakes inexperienced players make is holding on to the Q for more than one turn.
There are a couple reasons why players do this. First, because the Q is worth a game-high 10 points, they might assume that it will guarantee them a high-scoring play sometime down the road. They also might assume that a Q needs to be paired with a U, although that isn't the case.
When you find yourself with the Q, in many cases it's best to cut your losses and play one of those words, even if it scores poorly. Ridding yourself of the Q reopens the door to high-scoring moves in the future.
One scenario where you'd be wise to exchange is a situation every Scrabble has faced: a rack full of vowels. Imagine you're holding the letters AEFIIOO. You could play IF or FOE or OAF for minimal points — or you could exchange all seven of your letters and get a fresh start next turn.
Scrabble players are always thinking ahead. They don't just consider how many points they can score on this turn, but how each move they make will affect their ability to score on future turns. If you exchange your tiles and score zero points on one turn, but then score 25 points on the next turn with your replacement tiles, you're in better shape than having scored 10 points and 10 points.
It's not something you should necessarily do every game, but exchanging is often the difficult decision that needs to be made.
6. They don't bluff
Bluffing is one of the most exciting aspects of poker, and the same goes for Scrabble.
But amazingly, many casual players aren't even aware of this aspect of the game.
According to the rules, if your opponent plays a word that you don't think is legitimate, you can challenge the word before the next player makes their move. Players then look up the words in question in an agreed-upon dictionary — if the play is valid, the challenger loses their turn, and if it's not, the tiles come off the board and the challenger goes again.
Because the onus is on your opponent to challenge a word, players are free to play words even if they're not 100% sure of their validity. Occasionally, tournament players will even strategically play a word they know is phony if there are no appealing alternatives.
It might sound unethical, but to Scrabble players, bluffing is simply part of the game.
7. They 'fish' for specific letters
If you've played Scrabble before, you know the excruciating feeling of being just one letter short of an amazing word.
Maybe you've looked at a rack like CELNORU and thought, "If only that O were an A, I'd have NUCLEAR!"
As tempting as it may sound, it's almost never the right strategy to simply play your O and hope you draw an A out of the bag. Scrabble players call that "fishing," and it usually doesn't work out.
For one thing, the odds are against you — even the most plentiful letter in the bag, the E, makes up just 12 of the 100 tiles in Scrabble, and no consonant appears more than six times.
But more importantly, you're unlikely to score enough points to justify fishing. Playing one letter at a time usually means you're scoring very few points. Even if you magically draw the A for NUCLEAR and score 70 points, it may not be enough to make up for all the low-scoring plays you made on the previous turns.