League or knockout?
A round robin, where everyone plays everyone, gives the fairest ranking but the number of games grows fast: a single round robin with 8 teams needs 28 matches. When time is short, a single-elimination bracket is better — 8 teams need only 7 games. If the number of teams is not a power of two, some teams get a bye in the first round. A group stage followed by knockouts balances both.
Fair teams and draws
Taking skill level and position into account when generating random teams keeps games competitive. In a seeded group draw, the strongest teams go into separate pots so they cannot meet in the group stage. League tables usually award 3 points for a win and 1 for a draw; tie-breakers differ by competition — goal difference first in most leagues, head-to-head first in others.