I won't lie but I have watched tons of videos on how to fake big lips and honestly the video by Desi Perkins is the best one out there! The key is to overline the cupid's bow and merge that in to your natural lip line. Althoghth most MUA's will tell you that using gloss will help make your lips bigger, Desi suggests a more Matte lip to enhance your pout. I've tried both ways and I love the matte lip.
Here's the video; hope you find it as helpful as I did.