What I usually use is a poly leader with Maxima 6 or 8 lb monofilament as tippet.  How long depends on what kind of fishing I am doing and where.  I change it up depending on conditions and whether or not I am indicator fishing or how lazy I am feeling that day.
Favorite flies are golden stones, burlaps, egg sucking leeches, and a variety of other nymphs.  I caught my biggest fish on the Trinity by looking at the bottom of the river and tying on a large fly that matched the insects I saw there.  Don't be afraid to try something new or different than everybody else.
Hope that helps! 
 
 
Dawn