Here's my philosophy, when you're doing something you love, that you're passionate about there never seem to be enough hours in the day...when you're not into it or passionate about it , you can't wait for the day to end. At least that's my personal experience where there can be day to variances and some days we all just need a break.
I think entrepreneurs should fit time for creativity and coming up with ideas, working on product, and making new connections into their week. Making contacts and connections is probably the most important thing...they're the most helpful. At the end of the day it's not always what you know unfortunately, it's who you know.
Then, at the end of the day you need to take time for YOU. Rest, watch a movie, sleep. That's usually when you'll get your best ideas, when you're not trying to have them.