Buy her pie.
Carry cake and candy wherever you go? Otherwise, "big" girls are pretty much like small or medium girls--they're human beings will all the same thoughts and needs as anyone else.
You're a grown adult, you'll figure it out
be kind, honest and straightforward. Be prepared that she will not take you seriously or she might be surprised. People like us suffer a lot of rejection and ridicule, so she might distrust you at first.
You need BigGirlBate... It's packaged by ACME... it's really just a ham sandwich smuthered in gravy but the toppings determine the "race/color" u kno... mayo,hot sauce, curry *do not attempt in narrow hallways*
You will probably find that these type of girls will have low self esteem and would never make the first move. So I hate to say it but its ur job to approach her, just introduce yourself and be nice, nothing creepy lol .. If there's chemistry ask for her number to keep in touch :)
Stand by the road with a sign saying that you like big girls.
Just walk up and say "HI Sexy"