My skin type is dry and sensitive, so my approach to a makeup base is layer, layer, and layer some more. I start with Pixi pHenomenal Gel (£24), followed by Priori Tetra fx251 SPF 45 (£75), then at the moment (when I'm a little fake tanned) I mix Oxygenetix foundation shades Cream and Opal (£45) together with the Oxygenetix Oxygenating Hydro-Matrix Moisturiser (£46) (are you exhausted yet?!), applied with the Morphe M439 Deluxe Buffer Brush (£16). It gives a dewy finish with medium coverage.
A little goes a long way with the foundation, so a pea size is enough for medium coverage. I got a bit pump happy in the photo above; this amount would cover my entire face and neck with some to spare for building more coverage. On days that I want even more coverage, I'll either skip mixing in moisturiser or I'll go back in and build up the foundation with spot treating. Of course, you don't need this many products for the foundation to give results, I just choose to layer because I find this works for me at the moment.
If you have oilier skin, there is also an acne-control version of the foundation available, which contains salicylic acid to prevent spots and any further irritation.
Side note: my hand looks particularly pale in this photo, but the foundation does match my skin tone — promise!
Image Source: POPSUGAR Photography / Tori Crowther