Woody, soldering is part art and part science, but like painting a car, the result is a matter of how well you prep the surface, keep your tools in good working order, and use the right tools. Lead heatsinks used to be a thing, especially when people used 15-25W single temp pencils for soldering, but most of what Hams run into now won't need them. Along with a Soldering Iron, a Tweezers, small Hemostats, Dental Pick, and a set of small good quality dikes will be of help.
Once the board is prepped - I use IPA (Alcohol NOT the Beer!), 70-91% will work with the preference towards 91%. This can be obtained at your drug store.
Make sure your solder is either new or clean. I have some really old solder, and the surface oxidates. Wipe it with a rag with a bit of IPA on it to remove the oxidation or it will end up in your work. Speaking of solder, use the right size and type for what you want to do. Pb or Pb Free, and I prefer larger solder for PL259, and smaller solder for repairs and kits. I prefer a 60/40 Rosin core small diameter solder. If you want to use extra flux (and it is sometimes desirable) there are a number of brands of solder flux out there - they even make it in pen form. I'm still using the tin of Kesler stuff from 20 years ago (I should probably ditch it ;) ).
Iron choice - Don't even bother to buy a 25W iron. Seriously, just say No; don't even take one it someone gives it to you Free!
Because of the length of time it will take to heat, melt, an flow the solder, you will damage components and boards.
Like Paul mentioned, a 40-50W Pencil with adjustable temp will do most all kit building and rework.
The Tip type depends on what you are using it for. Sometimes you may need a sharp tip, others a blade, and most generally a slightly blunt tip.
I can't stress enough the importance of keeping the tip clean and tinned! Whether you use the copper coil method or the damp sponge method is a matter of preference.
The actual soldering is the art, and it depends on what you are soldering.
For normal through board components, you apply the heat to the circuit pad, add solder to the pad until it flows onto the component, then add additional solder to create the fillet. If you have a dual sided board, you want to make sure it flows though to the other side. Don't dilly dally though, when the job is done, remove the heat and let it cool naturally. A 60/40 Pb solder fillet will be shinny when done right, Pb Free will look like a cold solder connection and there isn't any thing for it.
Connectors generally require more heat, and it depend what you are soldering. For example, for a PL259 male, a 125W Weller gun is often the appropriate tool, though if it is cold where I am working, I'm not apposed to pulling out the 250W Weller :) Again, timing is everything. Too long and you risk melting the insulation or the connector.
Soldering SMD is a horse of a different color.
It generally involves 1st tinning the pad with solder, placing the component on the pad, and reflowing the solder (ether with a pencil or a hot air tool) onto the component.
Your success with this method depends on prepwork and the size of the component.
A Hot Air setup is useful for removing components and reinstalling them. They also work nicely to do heatshrink tubing :) Cheap ones are about $40 on Amazon.
This is a link to working with SMD components by KC9ON https://kc9on.com/ham-radio/smd/
Clean up - You want to board to look nice :)
I use IPA and a Q-Tip, for spot repairs. IPA and a tooth brush for larger items tends to get them clean.
FluxOff is a good product to use as a board wash.
Tons of informational material in YouTube videos!
, Ron WB9YZU