If you want to see a pretty good farming route for getting your paragon levels up in Act 1, check out this video!
It is common to start in The Festering Woods for a quick and easy 2 - 5 stacks of Nephalem Valor. From there you could go to The Cemetery of the Forsaken, or simply start in the cemetery. Once in the cemetery you will want to check the outside area for an elite or champion pack assuming you're on a low enough monster power to efficiently take them down. After that you will want to proceed into the various crypts.
After the cemetery, head south through the gates into The Weeping Hollow. The Weeping Hollow is a very popular destination for all kinds of farming ever since Blizzard increased monster density. The Fields of Misery is also a great place to farm and is usually the next destination. You will also have a chance to get an Act 1 key while in he Fields of Misery.
I like to include Leorics Manor as well as there are usually about 70 mobs inside that you should be able to clear within a minute or so.
After that you could head down to Halls of Agony level 2, rush over to the Highland Passage and on into The Cursed Hold. Clear a bunch of mobs in the Cursed Hold, town portal, leave game, resume game and start it all over again.