There are few things that separate 500+ from 700+ players. After recent changes in Elo calculation i dont belong to latter, anyway, maybe my tips will be helpful for you.
1.Watch what other players do. If you play against beginner players (Elo<400), you dont have to hurry for 1st task, just dont spoil any parks/pools, prepare gap for game ending. When having more advanced opponents, it's good to set aim for one of the tasks, and dont spoil any plots until you get there. I usually use one bis at this stage so no one get the task before me. Sometimes more bises are needed.
2.Bis balance: try to be one step ahead of opponents. If other player plays aggresively with bises, consider giving up on bis race and skip one of the tasks. After 3k games you will know individually, which players play more aggresively with bises, and which are more peaceful.
3. Skip tasks with low rewards: most players skip bis task, but temp task, 3-4 task, 2-5 task are also low rewarded, especially for second place. Depending what other tasks are its rarely worth doing them.
4. Pool/park balance: Its not possible to build all parks on all streets and all pools. Prioritise parks so you are sure to finish each street started.
5. Finishing: many players that lead with bises, fail to end game because they cannot fit final number. Last 2 numbers need to have really wide gap. Sometimes its better to skip one purple or pool, but have wider gap for last number.
If you get 1st to task, dont reshuffle. You can practice simplified counting cards and it will give you small advantage. Counting numbers really rough, just try to estimate how many low 1-6, middle 7,8,9 and high 10-15 had already gone. With effects its good to be more careful: if you see you missed many parks, consider to give up parks on one of the streets. If you see you miss many fences, prioritise them in next moves
