Aviate, navigate, communicate. Fly the aircraft, always know where you are, and then chat to whoever you need to (ATC, pax, boss).
Before heading to the bush, get into a maintenance org, and learn how to do all the pilot maintenance you can. Change a tyre, change a spark plug.
Read Section 7 in the POH on aircraft systems, then go through it again, and write down a list of questions on anything you are not clear on. Then go through that list with a LAME, and get a clear answer. Section 7 of the POH should be of more interest to a pilot than Playboy or Cleo.
When enquiring about the condition of an little used airstrip, ask if anyone would be game to belt down it in a landrover at 120 - 140kph (that's approximately your landing speed for most light singles). If there is any hesitation before they say yes, then there's your sign.
It's a requirement to do a fuel drain before flight. The second half of that reg is more commonly forgotten, and that is to do a fuel drain after re-fuelling ( before starting up to taxi). Always best to catch nasties before they get sucked into the fuel filter / fuel system.
Check the weather from more than one source. Look for the common information across all sources.
Check the weather for today, then check it for tomorrow and the day after. It's all very well to get from Point A to Point B today, and overnight, but a weather system coming through may mean that you are at Point B for tomorrow and the next day (and the day after....while the strip dries out).
Get a dual sim for your phone that does both Telstra and Optus. Think about investing in a Sat Sleeve that will turn your ordinary mobile into a sat phone.
Get a bluetooth compliant headset, so you can link your phone to your headset, and make calls in flight (push the pilot isolate switch to separate you from the pax). It means a quick chat to the boss or to the Gingerbeers may settle your mind / nerves.
A couple of muesli bars, extra water, a clean pair of socks, jocks, a toothbrush and a phone charger in the hand luggage weigh very little but will come in handy surprisingly often.
In advising a passenger (or the boss) why something can't be done, double check your facts and figures, be polite, and try and offer an alternative rather than just saying "no". Stick to the facts, and don't get into a slanging match (unpleasant with a passenger, career limiting if its the boss).
I agree with most of the previous comments - know your personal limitations, and always, always have a Plan B (and a Plan C, just in case).
On the day I got my PPL, my flying instructor said -
Right now, you have a full bag of luck, and an empty bag of experience. The trick is to fill the bag of experience before you empty the bag of luck.
At the time, I thought he was being funny.
20 years later, I look back and think how right he was.
Flying in the bush will introduce you to experiences, locations and people you would never otherwise meet. Some you will teach, others you will learn from (good or bad in both instances).