Re: Czech Nymphing
You can use it in Lakes - but its' really designed for rivers.
The key is a constant control and connection with the flies, - you can detect the smallest bite (my record so far is a 1 inch long parr), if the line stops, hesitates, just looks abnormal it's usually a fish. - I once fished 2 miles of river downstream doing step.. cast.. step and had at least one hook up each run through.
Remember that the flies fish at the bottom - or just off - and that you are always in control of them. - Tapered leaders aren't really necessary as you aren't too worried about a gentle landing and unfurling of the line - what you are bothered about though is the correct presentation of the flies, - and always make a strike at the end of the run through.
Also - use fluorocarbon for your leaders - as it's nearly invisible in water. Don't worry too must about going too fine as you may snag regularly - but don't use a washing line for a leader either.
Finally the flies are the killers - and you will be surprised how small you can go and hook up the bigger fish.
If anybody needs any more help - you know where I am!