I have to say that not using the aids and going manual gears is definitely the way to go to get quicker lap times. In my previous sim racing experience (GP1-4, Nascar, Indycars, GPL, Toca, GTR, etc..) I always went this way but with F1 2009 and 2010 seeing as it had been so long since I had done any racing I started off with most of the aids on and auto gears and then I kept putting off changing this until I started the Time Trial Competition where all aids and auto gears are not allowed. Best thing I did was to join in the competiton as it forced me to abandon everything and go fully manual. It's far and away the best way to drive, you are far more in control of your lap and changing gears when you want as opposed to when the computer decides is a HUGE improvement. The hardest thing I found to lose was the dynamic racing line which I was using for corners only and did struggle without it for a while. You gradually beging to recognise little things that help you decide where to brake and then it all just becomes automatic. Try not to use objects that can be destroyed as your braking markers though... I did this at one track and then suddenly it wasn't there and I was into the corner and off before I realised!!
Try without the helps but do give it some time and don't immediately go racing around the track at full pelt.. build up the speed gradually and find out how it feels without all the helps on. Not sure if there is a favoured track for learning... I turned everything off for the Wet Melbourne Time Trial and I find that quite a challenging track anyway but it wasn't too long before I was matching and beating my pre-manual times.