Its good to know WHAT missile is chasing you. Infared or heat seeker. A different sounding alarm/warning will go off for each so you will know what is coming at you. If its a heat seeker.... its advisable to turn your after burners off, with them one your like a huge "IM HERE COME GET ME" target. With infared.... flares will deal with them. It all depends on the aircraft your flying to.....
the older planes will struggle, no matter how good you are at flying them. Its just the way it is to be honest. Where as the newer ones like the F22 just laugh in the face of any missile coming its way.
It takes time to figure out what works best for you. Rememer if your flying in a straight line you wont out run the missile. (unless you dropped 50,000ft). Its trial and error

you'll soon get it.
For me personally.....
i always flew either the F14 and dealt with ground/air or the SU33 and dealt with just ground (one pass in the SU33 can wipe out an enemy tower)... i ALWAYS had height on my side, so any time a missile was on me i would firsty determine what kind them i would out run it by going into a deep dive and using chaff/flares. Dont use your chaff/flares to early either, its just a waste (even though you have an infinite amount) wait until the missile is right on your arse then give it what for
Theirs alot of veterans on here who can help no doubt, so if you get stuck then keep posting for help.