Find out as much as you can about her without being stalker-y. Then write a long poem or song (make sure you can sing recite it properly), weave in as many in-jokes and references to the stuff she likes as possible, if you spend less than half an hour researching it you are not putting enough effort into it, make sure to make a good poem carefully, it should be romantic, but not TO romantic, nor clichéd, and make sure it is HER notion of what is romantic, it should still feel normal and fluid and causal, while still having the effort put into it visible. Then, at some time when she isn't in a hurry, and there are no people nearby that she could feel embarrassed in front of, recite it to her. (and make sure you recite it with passion, not just read the words. And for f**ks sake don't look at the paper all the time.)
Then await her reaction, don't say anything until she does.
(WARNING: All I know about romance come from reading TV tropes)
EDIT: One thing more. The most importnant factor you have going for you considering your lack of physical atractivnes or a PhD, is CUTENESS. MAXIMIZE IT. However, never ever fake it (atleast not blatantly), she'll notice. Still, do not try to be seem manly, or clever, or dignified, those might be good things, but cuteness is probably your main card. Blushing is good.