As Tony says, make small changes at a time. Your aural memory is very short but you will quickly find out what you don't like to hear as your ears will get tired. Making lots of change quickly can confuse you too. People sill 'golden' ears can quickly identify what they want to hear and know how to tweak it. For the rest of us, just make gradual changes.

RTA shows you what you're changing but doesn't necessarily give you an indication of whether you will like that change. A 'flat' audio response is also pretty strange sounding.

Didn't someone have an excellent link to EQ basics?