I used to think this just happened to me!!!
I was fishing yesterday and kept getting tangles - mainly due to 'trying to hard' and getting highly frustrated at the rising fish not taking my fly....
I tend to find, that in some conditions, it pays to fish a single fly, and change the fly more often, than fish three. If the line is always like 'spaghetti' and you are fixing or changing the leader all the time, then the fly is out of the water.
A valuable piece of advice that I once heard in terms of catching more fish was "make sure yer flea is in the watter!"
Never a truer word said IMHO!!