I dunno, it really sorta depends on what you're racing, who you're racing and where you screwed up at on the track to decide wether to just sit still or pit out. Sometimes, especially with alot of... well less experienced ppl playing, if you spin out and sit there still, they'll come at you like nails to a magnet.
I don't mean in a blind spot on the racing line or anything, I mean even safely away from the line they'll do this. and of course to all the ppl that hit you, it's your fault they didn't slow down and swerve out of the way. So unless you wanna get banned for being realistic, i'd advise to pit out.
And with the exception of just learning the characteristics of whatever car/track you want to play with, single player WILL NOT help you. the only way you can learn online racing is by doing it. As stupid as the A.I. is, they generally aren't as stupid as we are when it comes to T-1.
And giving up the corner??? Again, you have to make a decision there.
Sure, you can hold your line and be 100% in the right by doing so. And the other guy could be totally reckless and hit you, either by cutting in too hard from the outside or drifting into you from the inside, but then your 100% correct ass will be out of the race. sometimes it's better to let the idiot on by and wait for him to hang himself a little further along. They almost always do. Then again, the other guy could know EXACTLY what they're doing, but do you? So you have to be able to figure that out - and fast.
I still get kinda nervous when it's three wide into a corner and I'm the one in the middle.
online racing isn't just about being faster. It's about having to make split-second judgment calls sometimes. and those judgment calls can only get better by simply getting out there and getting your feet wet.
Your 5 second head start idea is a pretty good one, but maybe too long.
I'd advise to pullover and accelerate as soon as the last car gets past you
I also advise not to just jump in a f-08 server or a LFR server without practicing with those cars for a bit... a pretty good bit unless the server is like almost totally deserted, then be cool to whoever is there and you might just get a few good pointers and decent set-up