Those who have found the pods of freshly stocked trout recently have racked up the biggest catches, but some bigger holdovers are mixing in here & there. Fish a spot, but if it's not producing, move on, don't linger. Lately the more water I cover lately, the better I do. I might come up empty in 2-3 spots, and then bang fish in the 4th. Nymphs & deeply/slowly fished streamers are the most reliable fish catchers in the cooler waters of the early season
Subsurface, try fishing Hendrickson nymphs, Bruce Marino & Rich Strolis both tie us DEADLY nymphs for this- ask and we will point you toward them. Hendrickson nymphs catch me a lot of BIG trout in April/May. A bigger #12-14 Pheasant Tail can also work well. Hendrickson Nymph patterns can also pull double-duty as early season stoneflies. #16 Olive nymphs imitating Baetis Vagans are also a good choice now, they are just starting up. Early Black & Early Brown Stoneflies (sz 12-16), Pheasant Tails (sz 12-18), olive/green caddis larva (sz 8-16), cased caddis larva (sz 8-16), midge larva/pupa (sz 16-20, especially in red), attractor nymphs (sz 12-18 in Red Headed Stepchild, Copper Johns, blue Lightning Bugs, Yellow Prince, Rainbow Warrior, and egg flies (sz 10-18) are still a good choice. Don't be afraid to fish some some gaudier/flashy/attractor-type nymphs, the trout sometimes show a preference for them, doubly true for recently stocked trout.