Use good glasses. A good glass is clear (not frosted, not blue, not stenciled with a pattern, nor made of metal) so you can appreciate the colour of a wine. It should be a tulip shape so that the space above the surface of the wine holds aroma. They are not necessarily expensive. Look in better wine stores. If you are keen on wine then buy better glasses – a wide range is available all the way to state of the art Riedel branded specialist glasses. It is bad etiquette to serve a guest’s good wine in tumblers, blue coloured glasses, or in straight sided or splay sided glasses. Remember that an inexpensive wine will taste much better if you serve it in good glassware. Drinking wine without good glasses is like listening to great music repeatedly through cheap low quality speakers!
The glass should be only half filled – this leaves an aroma space.