TL;DR: To raise your ELO-rank you need to play better and expect the same from other players.
I've looked at your recent game and immediately noticed a lot of mistakes.
https://boardgamearena.com/archive/repl ... s=97166359;
Your turn 1 is a mistake: clue red to carl instead of 1 to Purii; this is called a finesse - 2 plays for 1 clue, so after Purii discards 1r (or clues something - most good players in Purii's seat after you clue 2r with red would clue white to asutosh, a reverse layered finesse - 3 plays for 1 clue, expecting you to play 1g and 1w before asutosh plays 2w), asutosh will play leftmost card 1r and carl will follow with 2r; when you have clued Purii's 1r, he has the right to assume it's not 1r, because there is another 1r in a better position on asutosh, so he clues red to carl himself intended as finesse (or more likely a bluff).
Your turn 3 is a mistake: don't skip Purii to clue 2w (you may and in fact you do have the other copy of 2w already marked), instead you should clue Purii's 3r with red and you've caused it to be lost by cluing 2w; if the other copy of 3r is deep in the deck, you made it impossible to win (max score).
Your turn 6 is a mistake: don't skip all the other players to clue 2 to 2g on carl; in particular Purii has a useful 4y card that cannot be easily saved; you should simply play your 3w, seeing 5w and both copies of 4w that other players can clue, possibly delaying 4y discard.
There were a lot more mistakes by you and other players later in the game, but if you learn to play a better and more effient early game, you'll have less problems keeping all the useful cards in hands in the middle game.
PS. And if your question is instead about technicalities of ELO in cooperative games: it works the same way it has been working. Your still have an ELO value assigned and you can look it up by hovering over rank icon in the lobby. You will eventually reach 100 (Average) ELO, because you don't lose ELO when you end up with low score before reaching 100, but to reach higher ELO you need to learn how others play on this site using finesses, bluffs and other conventional tricks. The ELO change is based on a few factors, but most importantly average team ELO. A team that has average of 800+ ELO is expected to score 30/30 to gain 0.5 or even less ELO and will lose a few points if they score 29/30 and up to 10 ELO if they score even lower. A team with an average score of 200 ELO will still gain ELO if they score 27/30 or so and even more if they win the game (max score). Don't quote me on exact numbers. PPS. The best way to quickly climb to 700 ELO Master is to play about 50 games of 2 player avalanche (multicolor) variant - if you know what you are doing and have a good partner.
