Nails - don't worry if you're not interested/can't afford a fabulous mani-pedi, just make sure that finger and toe nails are short and extremely clean. Chipped nail polish is a total no-no.
Eyebrows - all the usual advice, get professional shaping if you can and then fill in wth a powder that matches your eyebrow hair colour
Wear fitted clothes - don't choose enormous floaty styles that swamp you, even if you're not very confident about your body.
Get to know your body shape and (very important) what you like about it and which parts you want to draw attention to.
Get properly fitted for bras (never at M&S) - be prepared to spend a bit of money, they are a real investment in both your look and your health. I'm at 34HH and cant' say enough about Bravissimo - fitting, range of styles and service are all excellent.
Wear clothes that you like, not just what you 'think' you should wear or what's in fashion. Excellent advice upthread about wearing jackets and coats with waists (can be impossible to find sometimes!) - much more likely to be flattering than a boxy shape.
Try to have fun with your clothes and overall look - it's supposed to be something that makes you feel good, not something you feel horribly anxious about. Don't be afraid of developing your own style.