There is still a lot of confusion regarding curation rewards (even among users that have been here for a year). I will show you how exactly the curation rewards are calculated. Be warned though, curation rewards are quite complicated!
WARNING: If the article doesn't completely load, try to refresh a few times. There seems to be a bug with this article.
Number of votes before you
Below you see a graph that shows you how your reward is being influenced by how many people have voted before you. As you can see the majority of the curation rewards are claimed by the first 5 curators!
DISCLAIMER: i don't have the exact formula so i had to simulate it. This graph is slightly more drastic than reality, but very close to the correct formula.
So you're probably thinking "oh that's easy, i'll just vote immediately after publication". Well, that won't work because there is a second mechanism called "reversed-auction" in place to prevent this (as explained in the next section).
Time after publication
Below you see the graph that represents how much of the curation reward you will receive based on time of curation. In the first 1800 seconds after publication a part of the curation rewards goes to the author of the post!
Voting power
This is the third factor that influences your curation rewards. After the hard fork of June 20th you can spend 2% of your remaining voting power per vote. So every time you vote your new voting power will be voting power * (98/100). Below you can see how your voting power changes when you start voting at 100%.
Your voting power regenerates exactly 20% of your used voting power per day (that's ~0.83% per hour, ~0.0139% per minute and ~0.0002315% per second). You can calculate yourself how long it would take to regenerate to a certain value based on your current voting power.
You can find your current voting power on www.steemd.com/@yourusername in the 17th row of the table on the left (don't forget to replace "yourusername" with your actual username!).
STEEM POWER
This is the fourth factor that influences your curation rewards. It only influences your absolute reward, everyone will earn identical relative rewards when voting in the exact same circumstances.
Voting weight
To make thinks even more complicated there is also a voting power slider when you have at least 500 STEEM POWER in your account. With this you can essentially truly curate how good you think content is. If you vote at 75% voting weight you used up 75% of the maximum 2% of your remaining voting power.
Reward pool distribution
At most 25% of the total reward of a post will go to the curators (and 75% to the author). The reversed-auction (as explained earlier) will determine the exact percentage going to curators in case any curators voted within the first 30 minutes after publication.
Example:
- Curators before you have already contributed 100 STEEM POWER total
- Only 1 curator has voted before you
- You have 100 STEEM POWER
- You voted when the content had been published for 10 minutes
- You voted at 100% weight
- The total reward pool for this post is $10.00
In this case 50% of the reward pool has been contributed by you (100 of the 200 total), you voted exactly at 1/3rd of the first 30 minutes at 100% weight and you voted 2nd (let's assume 40% as reward multiplier for that).
I will be using the following formula to calculate your curation reward: [total reward pool] . 0.25 . [reversed-auction multiplier] . [voting position multiplier]. Your rewards will be: $10.00 . 0.25 . 0.4. 0.33=**$0.33**. So in this specific case your curation reward is exactly 1/30th of the total reward pool of $10.00.
Had you voted at 30 minutes or later and the other curator came after you, you would have earned $1.50, which is 4.5 times as much! If you were the first voter at 30 minutes or later and nobody voted after you, you would have earned $2.50, which is the maximum 25% of the total reward.
Optimal strategy
The ideal situation will be if you are the first voter at 30 minutes after publication and at payout the post has earned 
In reality this is (almost) never the case. What happens in reality is that people eventually start to vote, similar to real auctions, but then in reverse. So the most optimal strategy is to constantly monitor how many votes and how much rewards the post has. Of course to do this completely accurately you need complicated software to calculate this real-time.
It's recommended that you do not vote more than 11 times a day at 100% voting weight if you can use SteemIt every day. When you do this you will have over 99% voting power available after 24 hours. You can vote as many times as you want, but after a few 100 votes you will receive less than 0.1% of the reward potential.
Don't forget to follow, resteem and browse my channel for more information!