The most common table arrangement is circle tables in rows. This is great for any event that might include a meal or reunion. One trick with this is to make sure you do not put your table too close together.
Next you have your rows of banquet tables with a head table at the front. This is great for a small area to fit a lot of people. You can use this for a meal or wedding as well and put the head table at the front. This is also great if you want people to interact more. You can also do this layout with round tables as well if banquet tables are not available to you.
Here is a great layout for conferences or a teaching sessions. These layouts allow everyone to see each other and interact well.
Finally here are two great layouts for a speaker at your event. It gives everyone a great view of the front and can be done in almost any room.
For more layouts for exact sizes of tables, here is the website! I have used it multiple times to figure out what is the best layout for my events!




