Finding the right foundation is the holy grail of make-up - no other product has the power to make or break your look, and no other product is quite so difficult to track down. In fact, even the experts struggle. "Finding the right foundation can be extremely tricky. I always compare it to finding the perfect bra - aka my worst nightmare!" says Ania Milczarczyk, Laura Mercier Make-Up Director.

On the eve of the launch of Laura Mercier's new Candle Glow foundation,  which blends radiant pearl mica with purified water for lightweight and luminous coverage, we quizzed Ania about the warning signs when your foundation isn't doing you any favours. "Not matching the colour of your neck/chest, creasing in fine lines during the day, getting overly oily or wearing off in certain parts of the face and some also do this weird thing where after a few hours they look like they're sitting on top of the skin," she says. If you suspect your face fits into one of the above categories, read on for Ania's tips on what to do about it - fast.

1. It's okay to try them ALL
"My best advice would be to try them all on. Make-up counter boys and girls everywhere will want to kill me for saying this but go and test them ALL out. Any you think may be a real option - wear for a whole day and keep checking on it in different locations throughout the day. I think natural light is the best indication. If it looks good outside in the middle of the day - you're most probably safe."

2. You don't necessarily need more than one
"How many shades of foundations you have depends on how your colour changes. For me, even with a tan in summer, I still don't get dark enough to need a new foundation - I can just put some extra bronzer on and get away with it. If you're someone whose colour goes back and forth quite dramatically it might be a good idea to have a fairly light and extra dark foundation and then mix the two to customise the exact shade."

6 foundation lessons that will seriously change your life

3. Leave your nose alone
"Leave the tip of the nose, cheek bone area and outer edges of the forehead free of coverage and simply put tinted moisturiser on those areas. I try to keep the foundation only where it's really needed to create a much more natural look."

4. Tools at the ready
"I think the best way to apply foundation comes down to personal preference. Even when I'm telling someone how I think they should do it I know that 100 per cent of the time they'll go back to doing it how they're used to and if you put me on a lie detector test you'll find I actually put mine on every morning with my fingers. However, I use brushes for all my models but then suggest for anyone who isn't sure, to use a sponge. Sponges are great because they create a seamless blend and take off any excess product while also filling in pores."

5. In the buff

"I love to really go over everything with a buffing brush using small circular motions. I also suggest blending your foundation down towards your neck to avoid harsh lines."

6. Prime for perfection
"Having a luminous complexion begins long before you put your make-up on. Healthy and happy skin shows through from under your make-up and that's where I think people really get their glow from. I exfoliate every night, moisturise every morning/night and put primer under my make-up to protect my skin from absorbing anything into my pores." 

6 foundation lessons that will seriously change your life