How can I see today's reputation increases/decreases, only. Also, I would like to see which increases were blocked by the rep cap
At the top of the screen, click the envelope icon to the left of your username to view your Recent Activity.
Use the filters to show the data you want, ie, reputation. (Summary only shows the top 5)
Your reputation will be shown via the boxes to the left of each item. The top number is the number of votes and the bottom number is the amount of rep you got.
If the 2nd number does not exist or is lower than expected, it means it has been rep capped.
This is the correct way.
You can also go to https://stackoverflow.com/reputation to view your reputation audit. Scroll to the end to see today's data. (/reputation will work on any of the sites)