Where to place favors on the table
When you are placing your wedding favors on the table you want to make sure that everyone knows which one is theirs so there is no confusion. Most of the time, they are placed in the middle of the table above each plate. However, if you are having a buffet style dinner you can place them anywhere on the table that makes it look good.
Where you place the favors on the table is less important than how you place them on the table. Don't make it look like you just threw them on the table and they are wherever they fell. You want your tables to look fabulous and not messy and thrown together. It can be so tacky when you place your favors wherever on the table, you want everything to have it's own places.
Where you place, the favors will depend on the type of tables. You may have long tables or you can have round. When it comes to round tables, you have less room on the table and they are more intimate. You will want to place them near each person's water class (located on the right) or right above the plates.
Also, you can place them in the middle of a plate and this will end any confusion over what is whose, but you will only want to do that if you want them to focus on the favors. If you went all out on your wedding favors and you want to show off your work or the expense, then you can place them in the middle of a plate. If you have editable things like cookies, and you didn't place them in tulle or packaged them, you can also placed them on a plate. This should only be done if you had fancy cookies done up. For longer tables you have more freedom because you have more room for your things.
You will find that your tables will have centerpieces, glasses (both water and wine or champagne), dishes (if a formal wedding) silverware, and possibly other things like a bowl of chips or something. Where you place the favors is not a big a deal. Just try to make the table look good.
Some people won't put the favors on the tables. You can place all the favors in a basket and place it near the exit so guests can grab a favor before they leave. You can also place them at the end of the line if you are having buffet style dinner. If you are going to place them at the end of the end of a dinner line, you will want to do that only if it is something edible. Cookies and mints are great options when it comes to edible favors. However, if you are going for a keepsake favor make sure that they are on the table, because they are going to be more expensive and you won't want to have someone take more than one just because there is only enough for one per guest.
However you want to do your favors, rather it is on the tables or not, make sure that they are placed neatly on the table or in a basket and that they are all tightly bundled so that you don't end up having someone pick up a favor and it goes all over the floor. If you are going to have something like tiny candies you may want the guests to pick it up as they leave so that you don't have some fall because the candies were all over the floor.