My personal opinion is that being able to do many laps without crashing or loosing control is far more important than being able to do the occasional very fast lap.
I just try to be consistent, after all the only person one can race is oneself. I'm new as well and not very fast 1.36.69 with the XFG. A couple of weeks ago when I started 1.45 was a good time for me. So I'm happy.
I prefer to use my own setup, this way I learn more and get a driveable car. Also I try to finish every race I start, if I'm behind because everyone is faster so be it, as long as I'm driving well I'm having fun.
If I meet someone in the race that is more or less my level and a good driver, I know it will be a fun race. If he is slower I'll study him a bit, see what kind of driver he is. If he is good I'll go behind him and look for an oportunity to overtake. If he is bad, I'll make sure that he won't ram into me the next turn (some when overtaken will floor down the accelerator), so you have to make sure you can put enough distance to take the next turn safely; don't forget to look in the mirror to see him bite the dust.
Faster cars, by definition anyone that gets close behind you is faster than you, if you get a blue flag, well just let him pass as soon as posible. If not well no reason why you shouldn't try and hold your position, this is a race after all. Of course some are so hot headed that they will be mad if you don't immediately dissapear, so instead of trying to overtake you they will try to push you off the road, these are usualy the kind that retire if they can't be withing the first 3.
Then are the good fast drivers, these will cleanly overtake you, if they aren't so fast as to dissapear quickly, follow them and you'll get an invaluable free lesson in driving well and fast.
As for hotheads, crashers, rookies, bad drivers, people that "once overtaken pit and wait somewhere on the track to crash into you", and other fauna of the sort; detect and avoid. In any case don't get into useless fights with them. And don't "press 1" happily, make sure you know the guy is a cheat, it's a well known trick "crashers" use to get rid of legit drivers, if not you run the risk of ending up in a "demolition derby".
Anyway this is the way I see it, drive well, be consistent, learn to make your own setups, finish every race you can, practice, and fast laps will come on their own. At least this is what I hope.
PS Sorry for the long post, I got carried away.