I always have three windows open in my internet browser. The first is steemit.com, the second is steemnow.com and the third is steemit.chat. My most valuable tool on steemi is Steemnow that is made by 
Disclaimer: I've used the profile of Penguinpablo because that shows the statistics on full capacity and glory! It shows the big rewards and how an interface would look like when you're a whale!
The tool shows me a few highly important things:
- My current Voting Power. Very useful to gain great curation rewards.
- The rewards from today and yesterday. I can check out which rewards I got and make my own analysis from it.
- Latest upvotes. This is a highly important one, because I can see who voted on my post with what percentage. I can also check their Steem Power and see who my loyal followers are. When I see someone new I can check out their profile as well. Besides that many people on the Steemit chat (especially and mostly really new users) say that they voted on your post but it doesn’t say so on steemnow. (Shame on you!)
- It shows the latest curation rewards. Not really big ones right now because my upvotes aren’t worth that much just yet. But getting there!
- Latest author rewards. Pretty important one. I can check how much SBD and SP I got from my posts but also my comments.
- Lastly, it shows all your posts and when you get a payout. Not really needed but also nice to have an overview!
As seen above it shows you the important stats you need to know in a clean interface. I highly suggest to bookmark it and use it to your benefit because it can really help you grow if you use it correctly with some analysis you make yourself!