Several threads on /r/AskHistorians have addressed changes in what people consider attractive in a female. For example, the "ideal female form" has varied over time (and space) with respect to body shape and bust.
I hear less about changes in what was considered attractive in a male. Other than, say, beards being in fashion and then out again, I can't think of much.
One reason is that men didn't really think about what made men attractive, and since most of our sources are men, we don't have much of a record. But is this the whole story?
Although it's a trend in adornment rather than physique, it's certainly the case that there have been periods in which males wearing wigs and full makeup was very much in vogue. A look at French rococo paintings will demonstrate that.
Again, until fairly recently (early-mid 1800s) wealthy men wore much more elaborate clothing- ruffles, lace, pastel coloured satins and velvets. They also decorated themselves with precious metals and jewels. Whilst men's clothing became much more demure (in terms of colour) and homogenous in the Victorian period, there were still trends for 'dandyism.'
What about for the lower classes who don't have much luxury in appearance?