Another keen DIY welder/fabricator here.
Material preparation tools are important. Use 1.0mm thickness or less discs for cutting.
For tubing and straight cut offs I use one of these.
https://www.machinemart.co.uk/p/einhell-ts-230-angle-grinder-stand/?da=1&TC=GS-060521050&gclid=CjwKCAjwq57cBRBYEiwAdpx0vdM3ZqGPHROpZ2kkGEGITMKLeEXbKj0WWmspAGSQN778JHQJVT6RTxoCz-IQAvD_BwE
Bought a 2nd angle grinder and fitted to the stand as a permanent set up. The switch is ‘on’ and then on/off is controlled by a foot switch (Again had to make this myself).
Lots of G cramps, mole grip clamps, magnetic angle tools are very useful.
Get an auto-darkening helmet. I use ESAB, as if you need reading glasses (its my age you know), ESAB can supply lenses to fit into the helmet according to your prescription.
I started on agricultural things, making benches, making racking for the workshop, mending lawnmower decks etc, etc. Made a welding bench with a steel top.
I recently repaired the catalytic converter on my daughters Peugeot 107. (The inlet tube from the manifold was cracking at the weld where it entered the body).
Preparation is the key to welding. Don’t just try to weld thicker sections together that have been cut at 90 deg, grind a 45 deg bevel on the edges. You want weld penetration, not for the weld to ‘sit’ on the surface.
Just make small tacks first, before completing the weld in full. Its easier to adjust/bend/tweak at that stage.
A welder does not want to be known as a grinder.
