The best way is to look at ticket prices for teams in your league and see what different teams set for theirs. Then you can base it off of how many games you think you will win and look for a team similar to that record and adjust your prices closish to theirs, keeping in mind they can be a little higher since you just promoted. Sorry if this wasn't much help, but I think it is the most effective way.
Murray/Harris/MPJ/Grant/Jokic - 2020 NBA Champs