Great idea Adam to get seasoned photographers to contribute more on the forum with helpful advice!
I might not fall into that category being an amateur, but I have a few years of Pentax shooting up my sleeve that enables me to give some tips on how to get the best out of the Pentax camera.
1. Have a picture in your mind of the style of photo you would like to create. This is the skill of "learning to see". This gives you a guide as to how you decide on an aperture and shutter speed, framing the subject in the scene, as well as other creative methods of taking a photo like panning, long exposure and zooming.
2. With subjects that you have no control over, be patient. It takes the most experienced photographers days or even weeks of waiting serendipitously to get their best shots of wildlife and nature. More than just "f/8 and be there", anticipate what kind of look you want of the subject and have your settings ready to shoot in an instant.
3. Shooting people takes a little intuition on how to pose them to bring out their character the most in portraiture. Try both candid and poised looks. Play around with your light source(s), whether natural or supplementary, and position your subjects in a way that flatters their profile and creates a dramatic effect to the portrait.
4. Children add an element of unpredictability and fast motion, which you have to work with. Combine point 2 with point 3!
5. Have fun in the process and make your subject also enjoy the shoot (where applicable!). Happy subject, happy photographer!