I just hit Paragon level 100 for my Monk. Starting the game from the launch of 5/15/2012. This day is carved in my mind clearly. It is a little slow for me to get this level just now as I only have a Monk and a Level 19 Wizard. But as I have got there, I have a few points to share with you.
First, make friends with Diablo 3 players or play with your real life friends. It is natural to have doubts on certain builds and items. I have joined a Diablo 3 fans community. There I have made two really good friends. One named Proce who specialize in Witch Doctor. And another one is Jacky who mainly play Barbarian. I have a workmate named Xiaoshuaige who is good at Barbarian as well. Even in patch 1.0.5, he can fight in Monster Power 10. The hellfire ring is under the help of Xiaoshuaige. Everyone contribute a Inferno Machine Portal can help you make a Hellfire Ring which in turn can increase your Paragon Level speed quite a lot.
Second, insert radiant star Ruby in your helm and one Hellfire Ring for yourself, one hellfire ring for your follower. I did not get it why there are still a lot of friends abandon the Hellfire ring to pursuit sheet DPS alone. The XP bonus from the three elements are the cheapest and most efficient. It would not affect much of your DPS or EHP.
Third, convince your partner to play with you. My boyfriend is a League of Legend player who was persuaded by me to help me get Paragon level 100. I ask him to play the same account with me when my paragon level stuck at 85. With his help, we talk about the Auction House, the items drops. It is much happier. We have more to talk about in the leisure time. He can share my enjoyment when one of my items have been sold out in the Auction House.
Take my three advices, and you would hit the level 100 soon and happy. Good luck!