I get asked a tonne about when in the actual makeup process (steps) you should apply concealer. A lot of people are under the impression that concealer should be applied BEFORE their foundation but in fact it makes much more sense to apply concealer AFTER any liquid or cream bases. There are a few exceptions however.
Here are a few guide lines that will hopefully help clarify some of this for ye.
* When wearing liquid, cream, mousse or gel foundations.....
Apply your concealer after these "wet" type of foundations as often times, the foundation in itself will provide adequate coverage. Also applying foundation after concealer will probably move the concealer and just require you to re-apply anyhow.
* When wearing powder foundation or powder alone.....
Apply your concealer before any powder products as cream or liquid concealers will cake over powders and enhance the problem.
* When wearing concealer alone.....
Apply concealer in a shade that perfectly matches the surrounding skin of the problem area (After oxidisation if applicable) and blend it into the surrounding area. Press a small amount of a finely milled setting powder over the concealer to set.
Brush away excess.
*If using colour corrector concealers.....
In this instance, apply the corrector PRE foundation as the shade will need to be covered and neutralised to blend in with your skin tone. Take care applying the foundation over the corrector in order not to disturb the coverage.
I prefer to apply my under-eye concealer after my eye makeup is complete if there is a danger of some of the product (i.e. eyeshadow or pigment) falling down on my under-eye area. It saves you some work in most cases. If I am using makeup that causes no fall-out then I will often apply my concealer before my eye makeup.
I have found that this is a personal thing so it's worth trying both ways and discovering which works best for your own needs.
Hope this helps!