Well, the races are soon (tomorrow in fact) and many of you out there have had to redeck your old hats and fascinators yourselves to save money, so here's a few tips (:
1. Less is more - you don't want an overcrowded look, because a hat or fascinator is meant as a decoration. Keep it simple.
2. Position the feathers/flowers/assorted other thingies at contrasting angles; don't have them all facing the same way, to avoid the 'matted' look. Don't even think about going there. >] "Spray" it out.
3. For variety between feather types, you can shorten/strip/cut feathers. Also, try grouping different lengths together for dynamics.
4. Keep to a strict colour theme, eg. the colour of your dress + black.
5. If using mesh/net, keep it above the mouth, otherwise it will inhibit eating, speaking etc. Not good.
>>> An awesome example of a simple yet effective, classy fascinator. Notice the little colour use, the spray effect, and the lack of stuff. very yummy ;) (from http://www.jaffahair.co.uk/)
<<< Another great spray effect example. This one is also monochromatic, but doesn't it just look awesommmme? (from http://www.bd-i.co.uk/)