I know how you feel because when I first started, I was spending 2-3 hours entering sweepstakes and i realized that is way too much time to spend.
I currently enter about 25 instant wins, 40 daily entry, 5 24 hour entry, and a couple odd entries every day. I can get through these 4 catagories in about 45 minutes. I also enter a few weekly ones once a week and a few monthly ones once a month. I then go to the new sweepstakes and check all of these catagories plus the one entry catagory. I enter usually 10-15 of the one entry ones. I also enter my wife for any of the one entry's that are eligible.
I used to enter tons of daily ones, but I have yet to win anything from a daily and I've been submitting for almost 2 full years. So, from my experience anyway they are tough to win.
last year, I didn't enter very many one entry ones because I didn't think you could win. Then, I won a trip to the Super Bowl through one of these. It was foxsports.com and I was the winner out of 6000 entries. So, I now enter as many one entries as I can or that interest me at least.
I've won lots of stuff from the instant wins, a couple things from 24 hour entry, and 1 thing from one entry.
hope this helps.