Our table plan was an A3 piece of card and smaller pieces of card in the same colours as our invitations.
(all from here)
Top tip: If you are still to make up your table plan I'd like to give you a piece of advice. Unfortunately I can't tell you who to sit next to drunk Aunty Mavis or crude Uncle Fred - although my suggestion would be to sit them together. No my advice would be on not doing and redoing the table plan. Get a large piece of paper and draw your table layout on it. Then write each of your guests' names onto small post-it notes and stick your guests to their tables. It makes it much easier to move people about and the repeated "Oh crap we can't sit Fred next to Blanche they hate each other" moments.
We did a first attempt and then left it taped to the back of a door after three or four reshuffles we settled on the final option. The buzz of conversation seemed to indicate that it worked ok.