Hi tosmatos,

Please have a look at PACE soldering/desoldering videos on youtube. They are dated but very good in general. You don't need a lot of videos, just the basics. https://paceworldwide.com/video/basic-soldering-lesson-1-sol...

You don't need to spend a lot of money so I'll keep it simple:

Get yourself a few kits of SMD soldering components and practice. Amazon, AliExpress, whatever.

Some notes on technique:

You will be surprised at the tip size that works well - usually slightly larger is actually better, just need to get comfortable with the angle and size.

Have a magnifying lamp or something like that to help you see better.

You should always use alcohol (70-99% IPA) and flux. Clean everything properly, then flux it, then solder it. Then clean after you're done. Have a few flux pens on hand. MG Chemicals sells these things. You can also get the bottle version and some empty bottles with syringes that mount on top.

Using a "shoe" iron tip is nice because you can angle it between the lead of the component (through-hole) and the pad, and this gives you a little entry way for your solder to flow. The flowing, hot solder will then naturally heat up the rest of the pad. This is a thermal mass effect.

The alternative of having the iron tip on one side of the lead, and the solder wire on the other is not bad either. This makes the solder "flow" across the pad, but it does mean you don't get the thermal mass effect of the first approach. You may need to do this in tighter spaces. Regulate temperature wisely.

For through-hole components, most often the hole itself is plated so it is a double-sided pad, give it an extra 0.5-1s for the solder to go to the other side appropriately.

Make sure you have small wire cutters and nose pliers. The nose pliers are very handy when you need to shape the leads of transistors or chips that have 4-5 legs exactly to the through-hole positioning. Not usual, but not uncommon to see staggered layout.

You will make mistakes. You won't know what you are doing because no amount of tutorials can help here. We have all busted boards for various reasons. Just don't electrocute yourself on high voltage capacitor banks.