I've had Rosacea for about 20 years, but only knew what it was for the past few years. I've found a number of things have helped:
Using only very bland pharmacy bought cleansers and moisterisers, no fancy perfumed ones with irritating ingredients.
Be gentle to my skin and not use too much heat or friction.
Don't do strenuous exercise in the heat.
Once a year I have laser treatment, which targets the over active blood vessels and broken capiliaries. This has really helped and made flare ups less awful!