One of the first topics discussed during a contest planning meeting is time-line, with the focus on how much time should be given to this phase or that – how long should people have to submit, select finalists, etc. That stuff is worth discussing in another thread but let’s hit an important aspect of timing that you don’t want to miss and really need leverage: traffic spikes.
Contest traffic comes in waves, with rushes at certain important inflection points for participants. Understanding when those are and lining them up with your promotional objectives can make a huge difference in the amount and type of exposure you get to, and virality (did I really use that lame word?) you can expect from, your customers.
Rather than spell it out for you, consider this image from Google Analytics of a recent and typical contest. See if you can figure out what’s happening at the different indicated points. A wicked cool prize to the first person who gets all points right, in the comments.