You’ve gotten great advice. As far as flies go, the stuff you already have should make a good start. You mentioned in some other posts that you bought stuff like woolly buggers and muddlers, and an Orvis assortment of 20 flies. If those were the 20 for 9.95 deal they’re all great for trout, and the buggers and muddlers are too. What to use and how to fish will depend a lot on the water. Getting advice from a local shop is always a good idea. Don’t know where you are in relation to these two, but here are two good ones to check out:
In Fridley The Fly Angler is a full-service fly shop, offering expert help on a wide variety of fly-fishing topics. We offer classes in fly-casting, fly tying, and rod building, as well as guided fishing and helping you arrange travel on hosted trips.
Near Minneapolis Fishing Tackle, Musky Tackle, Muskie Gear - Thorne Bros Online Store
Hopefully they can give you some pointers on stuff that’s hatching, and places to go and other pointers in exchange for a few flies and a couple spools of tippet and dry fly floatant or whatever else you might need.
As far as techniques, to keep it simple, if you see fish actively feeding, try and match it up with something close in size to whatever they’re eating. A lot of times, nothing may be showing so…
If it’s a stream, I’d start out heading upstream with a 5X tippet casting dry flies— like a size 14 Elk Hair Caddis if the water is fast and choppy, or a 16 Parachute Adams if it’s slower, slick water. Hit the current seams where faster water meets slower water around rocks, near undercut banks and deadfalls, where water tumbles into a pool. Places where a trout could hang out without fighting the current, but have a conveyor belt bringing food nearby and with enough cover (water knee deep or more, or under a shady area) that it won’t have to worry about getting picked off from overhead by an osprey or something.
Try and get a good drift without the fly dragging in current—the shorter the casts the easier this will be. Hit each good looking spot a few times and keep moving.
On your way back downstream, you can keep fishing the dry, or swing a wet fly or nymph fish through those same spots. You can also tie on a muddler and drift it back downstream in front of spots and twitch it a bit, hang in the current , let it drift back and come tight so it rises up and twitch it, You can sort of steer it into holes with your rod.
If it’s a pond or lake and you see fish rising, try a dry. If nothing is going on on the surface, use a nymph with your 5X tippet, cast out let it sink by counting 10 missiissippi’s and veeeeery slowly give it a twitch, strip an inch, let it fall…. Twitch, repeat. Etc. Cast out each time counting out more mississippis to let it get deeper until you hopefully find fish. After you’ve fished the same area a bit, move a bit to the side and try again to cover a stretch of water . If this doesn’t work, try fishing something bigger like a bugger or muddler, same counting thing, but use faster strips.
Here’s a link to the MN DNR’s main page on fishing to scout out some trout water , and other info that might be good to know Fishing in Minnesota: Minnesota DNR