I also read a lot of accident reports. Its a good way of highlighting the relatively small number of things that kill PPLs. Its great to have lots of knowledge and be able to retain it and recall and use it, but I'm just not that good. The accident reports distill the things that you really need to be cognisant of:
1. Always do a thorough pre-flight prior to the first slight of the day (otherwise known as an A check) and do a walk-round before every flight. Many have taken off with tow bars still attached because they looked but didn't see.
2. Always know your fuel situation, your consumption and don't trust your gauges.
3. Look out, look out, look out. Collisions average one per year in the UK. Listen out on the radio, look out of the windows (all of them), and try your damndest to know where every other aeroplane in the circuit is.
4. Don't fly into cloud. Unless you're a good, current IR/IMC holder, single pilot IFR operations when done un-planned and under trained, will kill you.
5. Use you carb heat frequently and for long periods and know the conditions under which its most likely to be required.
You might notice that controlled airspace isn't on this list. This is because with the advent of cheap moving-map GPS, we all have no excuse. Also, you're unlikely to harm yourself or others though may well pick up a hefty fine.
I don't do loads of reading on PPL syllabus stuff, but I do make an effort to know everything I can about the type I fly and I do make an effort to stay current. I practise short field operations, I stall it every third flight, both from S&L and a turn(deliberately!) Being able to aviate in my sleep has enabled me to get out of tight spots because it left me so much spare capacity to navigate and communicate.
In essence, its an attitude thing. If you don't lose sight of the five things I mentioned above then you probably don't need a huge wealth of knowledge.