Make your wedding seating chart in an afternoon
A wedding seating chart made in a spreadsheet cannot show you the room. Draw the tables where they will stand, drop each guest onto a chair, and see who sits with whom and who still has no seat.
Start with the room
Get the floor plan from your venue, or ask how they usually set the room up. Put the tables where they will actually go, and add the dance floor, the bar and the top table too. It feels like extra work, but it is the only way to notice that table 9 is right next to the speakers before your grandmother is sitting at it.
Seat the easy ones first
The couple, the parents and the wedding party already know where they are sitting, so start there. Then anyone with a good reason to be somewhere specific: divorced parents who would rather not share a table, older relatives who want to be near the door and away from the music, parents with small kids who might have to leave halfway through. After that it is everyone else, and you will probably shuffle them around a few times. That is fine, it is what dragging is for. Just try not to leave anyone on their own at a table where they do not know anybody.
Print two things
On the day you will want a chart by the door that people can read in a second, and a plan for the venue and the caterer with the seat numbers and dietary notes on it. Both come from the same seating chart. Building it is free at any size; exporting is free up to 15 guests, and €12 once if you have more.