Megan Fox has BEAUTIFUL blue eyes. These are one of her many striking features. Buy some blue contacts to have the same effect. To enhance your eyes, get some fake eyelashes. (Use the fake lashes for special events because it looks tacky otherwise.)
On a normal day, curl your eyelashes and just apply two coats of black mascara. Line your eyes with black eye liner for a smoky look.
As for Megan's lips... If you are not genetically blessed with luscious lips, then buy a lip plumper. If think that plastic surgery is ok and you have the money for it, then plump your lips through plastic surgery.
Buy a rich shiny lip gloss to enhance your lips. Buy lip glosses in magenta or a natural lip color. Her lip gloss tends to have sparkles in it. This reflects the light and makes her lips appear fuller. Buy lip gloss with shimmer and sparkles.
Get braces if you don't have straight teeth. Also, whiten your teeth if they aren't white.
To imitate Megan's hair, you will need hair extensions. If you don't have dark brown hair, then you will have to dye your hair.
Once you get hair extensions, tease your crown and curl your hair in two inch sections. Tousle your hair for a laid back bed head look. Hairspray it to set it in place.
Make sure to always have your nails perfectly French manicured.
Another one of Megan's trademarks is being tan. If you don't have tan skin, get a fake bake at the local tanning salon. Use spray tans and not tanning beds to avoid skin damage.
Get in shape. Make sure to build up muscle. Her look is strong and toned, not just toned. You need to show muscle, so go to the gym and do pull-ups, squats and crunchies. Also do a lot of running.
Get a bunch of tight and short dresses in fun colors to show off your legs.
Start wearing a bunch of high heels and leather boots.
Buy a lot of tanks in different colors to show off your arms. Megan Fox likes to wear tanks in bright colors like pink and orange.
Get a couple of skinny jeans. Buy a lot of denim mini skirts and short shorts.
Buy a pair of aviators. Buy a clutch and huge leather studded bag for different occasions. Also, buy a nice leather belt.
Get a cardigan to throw on your tank when it gets cold.
If you want Megan's trademark Transformers look then get an orange tank and a denim miniskirt.