1. There are a few specific things to get a flawless look to your foundation. A good blank canvas helps of course, so sort out your skin care first. Remember a lot of it (skin care) is a load of rubbish, well not rubbish but you don't get what you pay for a lot of the time. So educate yourselves ladies. I highly recommend paulaschoice.com. Paula is extremely informative and easy to understand.
2. Primer: This acts like a light veil over the skin so other products sit well.
3. Concealer: Under eyes and in the corners, fingertips work well and its quick, around the corners of the nose and chin (these are the reddest spots usually) Depending on the size of your blemishes and colour, conceal them first too, but you might have to do it again after foundation if they continue to shine like beacons.
4. Foundation: A lot of people proudly say to me they don't wear any makeup because its bad for their skin. BUT, foundation protects your skin. Most foundations have an SPF and even if it doesn't, it provides a physical barrier to the elements. Start in the middle of the face and work out, you do this so that by the time you get to the edges you don't have a lot of product left on your brush or sponge or fingertips thus reducing the danger of a LINE.
5. If you have oily skin, a powder is good. If you have drier skin, using powder can feel tight and uncomfortable. If you use a pressed powder with a big brush, the product is more evenly distributed. If you use a loose powder with a powder puff, it can get messy so lighten your load and shake it off before you puff your face. This is better for oily skin though, as it helps to absorb excess oil.
6. Voila! You're beautiful.