Get an elevated view

Try and get an aerial or elevated view of the water you are going to fish.
If there is weed under the water, from your wading position it might look like a solid carpet of weeds, but there are always channels in the weed.
A lot of times, the fish will be deep in these channels between the weeds. If you fish dry only the fish might not come up so high. If you fish a dry dropper to control the nymph's drift between the weeds in the channel is very ineffective.
Go for a single heavy nymph. It is easier to control and less likely to get hooked up than when fishing two flies.