is there shortcuts for finding the equivalent reistance for any given circuits.also how to identify thru which part current does not flow,easy mehod to find the p.d b/w any 2 given points ifeel veryh difficult in these plz help me at the earliest

there are a lot of easy methods for different kind of questions but i suggest you to stick to basics for tough questions like KVL, KCL, and normal series and parallel combination of electric devices...

star to delta and delta to star are very usefull in finding equivalents of capacitors and resistors rspectively.

and note that any competitive exam like JEE or AIEEE dont ask big and complex circuits, which consumes a lot of time.