「[少]{すこ}し」 is basically an adverb, but it also has a noun-like usage as well, which allows particles such as 「の」 and 「は」 to follow the word directly. Any monolingual dictionary would mention this usage, too.
「少しのお[金]{かね}」 = "a small amount of money"
「少しの[我慢]{がまん}」 = "a little patience"
「少し」 in 「少しは」 is also used like a noun, but in this case, I would highly recommend that you remember 「少しは」 as a set phrase meaning "in some degree", "in some small measure", etc.
「少しは[気]{き}にかけて」, thus, means:
"Please care a little about me.", "Please pay just a little attention to me.", etc.