You've come to the right place! Asking questions is always good. It's how we learn. I've learned a lot by asking questions right here on these forums.
My own shooting style for macro is handheld exclusively. I'm a bug chaser. I need the freedom of movement and mobility that hand-held shooting allows. Do I miss a lot? Sure do, but when everything comes together, I'm really happy. Are there others getting better shots than me? There sure are, but my own results have improved a lot since I started, in no small measure from seeing what others have done and how they've done it, often right here on the Pentax Forums.
AF? No. The dedicated macro lenses I use most frequently are the Sigma 70mm f2.8 EX DG and the Sigma 50mm F2.8 EX DG. Both are AF but I use them in manual focus when shooting macro. Along with these macro lenses, I've done a fair amount of shooting with
reversed lenses, both directly on the body, on a body with extension, and reversed onto a longer lens. This type of shooting is trickier as DOF gets thinner, you lose auto diaphragm and gain a darker viewfinder. They are also only MF, too. In exchange, you get higher magnification, which I like because I'm often shooting insects that are quite small, or "portraits" of larger ones. I'm shooting single shots instead of focus stacking, too.
Flash? Yes. I'm usually using the built in flash on my cameras (K-S2 and KP) with a
potato chip tin extender/diffuser to bring the light out to the subject, otherwise I'd be working in the shadow of my lens. The flash is usually set to manual, as a lot of my lens combinations would not work with PTTL auto exposure. I play with fllash power output for exposure. Sometimes I'll use a more powerful auxilliary flash (also set to manua)l and, as with my use of the built in flash, adjust flash power settings until I get the right illumination.
I usually shoot in live view with focus peaking, sometimes with magnified live view. The K-S2 is actually better than the KP in this regard, as the
peaking indication of the KP cuts out in some circumstances when you press the shutter release. I'm not sure why it was designed to do this, but it does. Sometimes the fully articulated screen of the K-S2 (which is also found on the K-70) offers more flexibility with shooting angle than the tilt up/tilt down screen of the KP.
Extension tubes will have the biggest impact on shorter focal length lenses. 50mm of extension on a conventional 50mm lens gives you 1:1 macro capability. You can probably get 1:1 with your M 50mm f4 macro with 25mm of extension, as its focus mount has extension built into it. Beware though, that too much extension on too short a lens can result in the focus point ending up being inside the lens!
There are as many ways of doing macro as there are people shooting macro. The thing is to find the combination of tools and techniques that is going to work for you. What others have suggested here are starting points you can build on to create your own way to shoot macro that suits your subject matter, your shooting style, your way of doing things and your vision. Seeing what's possible is always helpful. Other people's work can be inspirational-and intimidating! Play, tinker and test. Learn by doing. Shoot and have fun!
Some threads where you can see what others are doing (and ask them how they do it) include:
The Macro Flower Club Show me your insects Spiders "Macro" lens club Macro by any means necessary club The Raynox Macro Club
And some links to other resources that I have found extremely helpful;
CHEAP MACRO -- Buying or exploiting a lens for ultraclose work http://extreme-macro.co.uk
Hope this helps.