Wine glass placement on the table varies by country, customs, and practicality. Even in the US, there are different recommendations by different wine and food experts.
Your restaurant manager, chef, or events planner may have specific ways in which they want you to set the table. If so, set it according to their instructions.
The general rule of thumb for glasses is to place the water glass at the most convenient place to the right of the plate setting, generally just above the tip of the knife or slightly more lateral to the right. It is placed for the convenience of the guest to reach and drink from, and for the server to refill.
If you are setting a table for a formal dinner that you know includes different types of wines with different courses of food, the water glass should still be convenient, somewhere near the top of the knife. Then going from about 3 o’clock back, counterclockwise to 12 noon, the glasses should be placed in the order they will be drunk.
A common wine glass placement for a general setting where you don’t know what order wines will be drunk would be the red wine glass (usually the largest wine glass), placed at about 12 noon, a white wine glass (usually slightly smaller than a red wine glass) to the right at the 1 o’clock position, and a sparkling wine glass further to the right at the 2 o’clock position just above a water glass.
This setting might be used just as a general, fine dining setting or perhaps used for a wedding reception. It would allow for a toast of sparkling wine at the beginning of the meal, a white wine to go with a soup and/or salad, and red wine or full-bodied white wine to go with the main entree.
As a server, you may need to bring glasses already poured with wine to the table. In that case, place the glasses in the correct position as unobtrusively as possible.
It would be great if you were so unobtrusive that the guest did not even realize you placed glasses there.