Just keep doing what you are doing
keep the end of the line well greased up and whilst it is upstream watch it like a hawk, if it does anything odd, pauses, stabs or dips then lift, often it is the bottom but a good deal of the time it will be a take.have a read up about mending, throwing a loop of line upstream (kinda like kids skipping) to insure that the nymphs drift is drag free.
some will say you shouldnt fish the nymph downstream, fishing is fishing and if you are enjoying it then ignore them... so long as you are compliant with the rules of the fishery then who cares
when you move onto dries the same principal applies, cast upstream , mend the line to make sure the dry drifts drag free...
Hope that helps