I have already achieved my goal of reaching the #1 ELO ranking, so I'll share my strategy. Hopefully someone can find it useful. All (90+%) of my games are 3-player games.
Round 1:
I like to always start with 888 for the first game against new opponents. In 90%(?) of games this will give me the turn 1 bonus of 2 points and 888 is almost never countered turn 1. Often the opponents will have wasted their 6s or 7s without getting the bonus.
Turn 2, I'll often play something low like 334, 444, 445 or 555. The players who played low numbers last turn will play high numbers this turn, so I just sit back and let them expend their 6/7/8.
Turn 3, I play 999 if no one else has done so. The other guys are saving their 9's for later, so this is usually pretty safe. Sometimes I play 999 on turn 2 instead though.
Turn 4: hopefully, the opponents have occupied both 6's or both 7's so that one of them is safe for me for the last turn. I leave this for the last turn and try to fill up the smallish numbers for 1 point apiece this turn.
Turn 5: play 5/6/7 safely. If both are expected to play larger numbers, I can feel free to pick up small numbers.
Round 2:
I assume the opponents will play their high numbers early this game, since I did well with that strategy in the last game. So I will try to put more focus on leaving the high numbers for the end.
Turn 1: I start pretty defensively. Something between 334 and 666.
Turn 2: good chance to win the hand with 888
Turn 3: circumstantial
Turn 4: circumstantial
Turn 5: the last turn of the game. The point in this round is to be the one who ends up with more points than his opponents, NOT to score as many points as possible. How many points is the maximum the other players can get? Any players that can only beat you if they get certain numbers? What will the other players play to maximize their scores? Any players that has only one good play?
Notes:
I think the easiest opponents are average-rated opponents as they are the most predictable and don't think that deep.
The meta might at some point change and make my strategy very bad. Be aware.
My above strategy is not fixed. It varies based on how I predict my opponents.
I play the same digit thrice quite often. The counter to a high,high,high meta is to play high,low,low.
Opponents tend to leave 9's for the last turn and not be able to use them since two players have 9's. It is much better to play a 6 at turn 5 and get 11 points than to play a 9 that gets blocked and gives you 0 points.
General logic/tactics:
When playing two or more different numbers, then after you have decided the first digit make the whole number as small as possible. Example: assume x is high, y is low. Always play xyy, instead of xxy. Or yyx instead of yxx.
Numbers that have been expended by all your opponents are safe. Take advantage of this.
Your opponents are playing with a relatively low degree of randomness. You can predict your opponents pretty well in situations where there are few tiles remaining.
Number values give most post points in a game. Then, bonuses and number of tiles played.
Round 1:
I like to always start with 888 for the first game against new opponents. In 90%(?) of games this will give me the turn 1 bonus of 2 points and 888 is almost never countered turn 1. Often the opponents will have wasted their 6s or 7s without getting the bonus.
Turn 2, I'll often play something low like 334, 444, 445 or 555. The players who played low numbers last turn will play high numbers this turn, so I just sit back and let them expend their 6/7/8.
Turn 3, I play 999 if no one else has done so. The other guys are saving their 9's for later, so this is usually pretty safe. Sometimes I play 999 on turn 2 instead though.
Turn 4: hopefully, the opponents have occupied both 6's or both 7's so that one of them is safe for me for the last turn. I leave this for the last turn and try to fill up the smallish numbers for 1 point apiece this turn.
Turn 5: play 5/6/7 safely. If both are expected to play larger numbers, I can feel free to pick up small numbers.
Round 2:
I assume the opponents will play their high numbers early this game, since I did well with that strategy in the last game. So I will try to put more focus on leaving the high numbers for the end.
Turn 1: I start pretty defensively. Something between 334 and 666.
Turn 2: good chance to win the hand with 888
Turn 3: circumstantial
Turn 4: circumstantial
Turn 5: the last turn of the game. The point in this round is to be the one who ends up with more points than his opponents, NOT to score as many points as possible. How many points is the maximum the other players can get? Any players that can only beat you if they get certain numbers? What will the other players play to maximize their scores? Any players that has only one good play?
Notes:
I think the easiest opponents are average-rated opponents as they are the most predictable and don't think that deep.
The meta might at some point change and make my strategy very bad. Be aware.
My above strategy is not fixed. It varies based on how I predict my opponents.
I play the same digit thrice quite often. The counter to a high,high,high meta is to play high,low,low.
Opponents tend to leave 9's for the last turn and not be able to use them since two players have 9's. It is much better to play a 6 at turn 5 and get 11 points than to play a 9 that gets blocked and gives you 0 points.
General logic/tactics:
When playing two or more different numbers, then after you have decided the first digit make the whole number as small as possible. Example: assume x is high, y is low. Always play xyy, instead of xxy. Or yyx instead of yxx.
Numbers that have been expended by all your opponents are safe. Take advantage of this.
Your opponents are playing with a relatively low degree of randomness. You can predict your opponents pretty well in situations where there are few tiles remaining.
Number values give most post points in a game. Then, bonuses and number of tiles played.