I like a 5 or 6 weight rod for most of our local rivers. It is not uncommon for me to have a sink tip ranging from 2 to 6 feet and for this reason I usually prefer the 6 weight. Trust me if you will be throwing 2 to 4 inch bait fish patterns with a sink tip all day you will be glad you opted for the 6 weight. Sometimes a floating line with a lightly weighted fly is the ticket and a 7.5 foot 3 or 4X leader is perfect. If you are in deeper / faster water and a sink tip is necessary, 3 feet of straight 3 or 4x tippet is fine. A typical down and across presentation usually works well. Use your mending skills to swim and sink the fly into would-be fish holding spots. As I work my way through a run I will let the fly swing through the first time. If I get no action I will swing through the same spot and impart a little action to the fly using the rod tip or my line hand. If I still get no action I will swing through again and this time use a full on jerk strip trying to elicit the predatory response (you are trying to piss the fish off so much that they can't stand not to eat your fly). Take note of the first fish you catch each day. What were you doing when he ate? What type of strip did you use, was the fly deep in the water column or shallow, did he hit it aggressively or just tap it? Go to school on the first fish you catch and try to repeat that presentation as closely as possible. After a few outings and several fish you will get the hang of it.
As far as patterns go I personally am fond of Sculpin patterns. The "Headbanger" series from Rich Strolis has been getting a lot of attention from me recently. Kelly Galloup has some great streamer patterns on his new DVD "Streamers on Steroids" (in stock now) that were designed specifically for big Trout and his Zoo Cougar pattern is possibly my all time favorite streamer. Muddlers, Buck tails and Buggers all have their place within this type of fishing. The Shenks minnow in white has been getting a lot of play on our local river, the White Clay and don't forget about Crayfish patterns. Crayfish patterns swung around rocks right before dark can be just the ticket when that big ole Brownie decides to strap on the feed bag and fill his belly.
Regardless of your river, gear or pattern selection, give this streamer fishing a try these next two months. Once you feel the bolt of lightning you will be glad you did.