I'm not 100% sure if that "early in the day" thing always works. My reason is that when a meme is submitted, it only stays near the top of the 'Latest' section for an hour until a whole new batch of memes comes in on top. If a meme doesn't get enough views and votes in that first hour on to get a decent position in the 'Hot' section (i.e. a position that people are likely to scroll to), the likelihood is that the meme will just disappear from sight, and go mostly unnoticed.
For that reason, I think a better idea is to find the times of peak site traffic, and try to submit memes so that they release during those times. I'm not completely sure though.