QUES: Despite this many gambling players attempt to beat the game

correct the punctuation.

CORRECTED: Despite this, many gambling players attempt to beat the game.

QUES: Find out enough about the holiday flat size equipment price location general conditions of agreement

correct the punctuation.

CORRECTED: Find out enough about the holiday flat (size, equipment, price, location, ..., general conditions of agreement)

QUES: Immediately after the reservation is necessary for obtaining a visa

correct the punctuation.

CORRECTED:
Immediately after the reservation is necessary for obtaining a visa.