Re: Piling up of my line
Zero limit is right about the leader troubles.
On mending, one of the tricks is you have to mend before you have to mend. By this I mean once the current has already put a belly (bowed section downstream of the fly) in your line, it becomes much more difficult to achieve a mend without moving the fly. This is because all the slack has been taken out of the line, on top of the fact that a line under tension is likely to already be partly pulled under the surface.
Try to make your cast land with some slack already in the leader, and then do your mending before all the slack is pulled out of the line. Doing all this will take some practice, but eventually it will be easier than I'm making it sound.