thump

Your best bet is to use a GDO (guaranteed day off). They are 3 consecutive days off that are pre-awarded before the monthly bidding begins. They do not have any credit assigned to them, so it wont change how many total days you get off, but it is guaranteed before monthly bidding begins. You only receive two GDOs per year. You can use them back to back, or partial, but you can't use two days here and the remaining day elsewhere. GDOs also can't be used in close proximity to holidays. I forget the specific days prohibited there.

After that, you can bid for the days off through the normal monthly bid process. If you are a junior line holder, it helps to bid voluntary reserve if you are desperate for a specific day off.

After schedules are awarded (line/reserve) you can try to drop the days, but that is very difficult unless it's a slow month (I.E. not summer/spring break/christmas/new years).

Trade board, but that's hard unless it's a day trip or two day trip.

Lastly, if it's something important like a baptism etc, you can ask the chief pilot for the days off in advance.

And "extra lastly" if that's a thing, you can always call off unavailable (and get an assistant chief pilot call) or you can call in sick.