Hi Brisbane Shooter Welcome aboard.
DOF doesn`t have to be that thin.
What aperture are you shooting at?
Its not uncommon to use f16 or f20, keep an eye on shutter speed.
I would suggest that first and foremost stand or sit/kneel as comfortable and steady as possible. Minimize your movement first. Be a tripod.
No point in trying to lean fwd or back when you are hunched over, you will only sway around and get uncomfortable pretty quick..
Keep your body comfortable and relaxed and steady, moving in or our with your feet, or slight body movements.
I would typically be close to the minimum focus distance of the lens, ie about 30cm away, then get body comfortable and steady and as close as practical , then use lens to fine tune. If auto focus has trouble, adjust manually.