About the lemon-in-hair technique, I used to slice a lemon into thin crescents and rub that on my hair, on the top and on the sides, and I'd go outside all day not worrying about it. I have a friend who just takes RealLemon and puts it in coton balls and rubs that on her hair, and it worked just fine.
My beauty tips:
Brush your hair everyday, and do not wash it everyday unless you do sports everyday.
The only thing I use on my face (I am turning seventeen this summer) that has worked wonderfully for me (I have nice skin luckily) is Dove 1/4 moisturizing bar of soap. I wash my face with it twice a day, and then I apply a moisturizer, either Nivea Soft or Aveno (those work best for me).
Brush your teeth at least twice a day; a beautiful smile is always dazzling.
Before taking a bath, take a quick and harsh shower. What I mean is to scrub yourself really really hard under the shower. Who wants to spend hours in a beautiful smelling bath with all their dirt seeping through their skin in their seemingly clean water?
Avoid applying eyeliner on the lower inside of your eye as a rash straight line. Try to make it softer.
When applying mascara, usually applying two coats is sufficient, and make sure you apply the second coat when the first is still wet, otherwise you end up with bristly lashes. Not good.
Go easy on the shimmer: you don't want to look like a frosted cake. For everyday makeup, either shimmer on your eyes or shimmer on your lips will do. Both will look like too much for everyday.
Use a bronzer to give you a healthy glow. Suck in your cheeks and apply it to the part that sticks out the most, to your forehead lightly, the bridge of your nose, and your chin lightly as well.
DON'T OVERTWEEZE your eyebrows! They can take a while to grow back in, and sometimes they don't. They're meant to frame your eyes, take care of them! If this is your first time, either get your mum or a salon esthetician to do it. It's honestly a good investment for your first time. Then, you can just keep following their shape. TELL THEM YOU WANT IT TO LOOK NATURAL, or you might come out looking like them (they have ugly pencil thin eyebrows often).
Drink a LOT of water. Pretty girls ALWAYS drink a lot of water. It hydrates your skin and keeps it elastic.
Eat a lot of vegetables and fruits: they give you a natural glow.
If using liquid foundation: Try mixing moisturizer with foundation, about two parts foundation to one part moisturizer. Mix it on her your palm or on your face and gently spread evenly. It looks sheerer and more natural.
When waxing, always have oil with you to remove whatever wax remains on your skin.
Nene's body scrum is amazing: olive oil and sugar. I prefer using soap afterwards, just once, because I don't like the oily feeling after it. If you use soap (Dove for me again!) afterwards, you just feel silky!
I have TONS more tips, but I have to go for now. Try them, and share yours! Later!