I've been doing what I call the "everyday Marilyn look" for much of my adult life. It's easier than you think! Here are a few tips if you want to marry classic hollywood with modern elements and wow on a daily basis!
1. The Hair Color
Marilyn is BLONDE, this is the singular most important element of the Marilyn look. If you can't go to a professional colorist (I don't, too expensive) just box it! It's high maintenance but whatever, it looks amazing. Try Feria Platinum hair color and remember to keep up with your roots. To eliminate brassy, yellow tones and make the best look possible try a purple shampoo. Scroll right to see some examples of good blonde hair care products.
2. The Hairstyle
Curled hair is a must, if you want to go with a Marilyn Vibe, any sort of body is good as well, wavy and textured is better than flat and straight. I use a straightener to curl my hair up and it works really well, make sure to use lots of hairspray! Another tip is to curl all of your hair and then brush it out into a softer curl. This is how you get more vintage hair.
3. The Makeup
A red lip and a heavily mascaraed eye is going to do the trick, for more casual day's skip the red lip in favor of pink. Her makeup is never overdone, so don't go crazy on the eyes. A slight contour on the cheeks and a pale pink hilight will add dimension to the look as well. I recommend the Urban Decay baked bronzer and pretty much anything from the Naked line for face.
4. The Wardrobe
The modern take on this look enables you to do pretty much whatever you want. Marilyn looked great in primary colors, so for example, here's an outfit I wore for this 4th of July. little scarves and outfits that work a curvier frame including high waist-ed flowy shorts and button downs work well together. Skater skirts too. It's all about finding things that fit your body.
Also, Marilyn has a collection at Macy's with inspired looks with a modern twist. The collection rests on fit and flare dresses and jean jackets. Polka dots and stripes are popular for Marilyn too.
5. The Confidence
Marilyn gave off a great confident attitude so be proud of your look, your beauty and never let anyone take your shine. Marilyn's look is just one way to bring out your own beauty. So strut, pose and love yourself!
I spent a large amount of time hating myself, and realizing I had a little bit of Marilyn in me helped me get over it, and you can too, if you want to emulate the look or not. Confidence takes time, and so does being comfortable with yourself.