Watch out for the weekends, that is when the "sleepers" come out and play. Amateur players with a few extra bucks that make a play on their favorite team or heard a real convincing play listening to an analysis on the TV/radio.
Sharps play everyday, and can keep up anytime of the week. Less amateurs during the weekdays, so the public is not so "public" then.
Books follow suit, I have noticed that on the weekends in the MLB and NHL the favorites are more likely to win.. books squeeze out the juice on the winning side with a -140 to -200 ML price... making it not worth your bet. You have a better chance of betting on the dogs and winning on the weekdays for more value.
Games played during "primetime" I believe are also inflated, so for instance be careful of NCAAF saturday game at 8pm EST., etc. Too many eyes are on that game.
MNF should be one of the easiest day to cover. After grinding it out all weekend with the books and being down, Vegas gives you a chance to catch up or reduce your losses. This keeps you playing and doesn't totally bury you, that way you come back next week and lose a little bit more or the rest of what was left.