How you interact with your servers can tell a lot about you. If you treat servers as people who are there merely to meet your every whim, if you refuse to thank them when they assist you, or if you talk to them in a degrading way, that behavior actually reflects negatively on you. (In fact, some employers who interview candidates over meals will refuse to hire someone who demonstrates disrespect to the serving staff.)
Typically, food plates are lowered on the diner’s left and removed over their right shoulder, but it depends on how much space the servers have to move around tables. Liquids are the one exception, as they are served from the right (where your glasses are located). Knowing this will allow you to (slightly) lean when a server approaches your table.
If you need anything, let the server know, but do so when they are close so you don’t have to raise your voice...and certainly never whistle, snap your fingers, or yell, "Hey, you!" A great server with an appropriate number of tables will check in on you regularly, anyway.
When you are finished with your meal, place your fork and knife parallel to each other horizontally across the center or diagonally with handles to the right to signify to the servers that your plate can be removed.
Finally, remember to thank your servers...both with words and with an appropriate tip (20% minimum, in most situations). Just as your disrespect reflects on you, so does your graciousness!