Given that Pisound Micro requires soldering own parts, I’d like to share some efficient tips for getting good with soldering quick. 
Here’s a list of things to keep in mind while soldering:
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The solder flows to and sticks to surfaces that are hot enough.
- This means that you must always heat up both, the pin and the pad at the same time.
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Be aware that some pins connect to planes of copper, such as the GND contacts.
- This means the heat up time is much longer for soldering such pins, compared to regular pins that connect to signal traces. Patience is key. Having a blob of solder on the tip of the soldering iron can transfer heat better.
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Sometimes the surfaces (or one of the surfaces) that you want to solder together have oxidized and prevent solder from sticking and forming a nice cone, even if the heat is right.
- This is solved by flux - there’s flux in the core of the solder wire, so applying some more fresh solder at the place that won’t stick can help deoxidize the area. An alternative is to apply liquid flux to the contact areas externally, there’s some convenient syringe options.
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The phases of soldering a pin:
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Heat up. During this phase, make sure to place the soldering iron to touch the pad and the pin at the same time. Don’t use any force, touching the right place is enough. Occasionally apply solder wire at the place where the pin, pad and soldering iron meets, to know when the temperature reaches solder melting point.
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Solder flow. Once the area reaches solder melting point temperature, bring in just enough of solder wire, not too little, not too much, just the right amount so it all flows to form a nice cone shape. Once it is flowing, prefer targeting just the pin and pad with the solder wire. After delivering the solder, move the wire away, but keep the soldering iron in contact for another 2-3 seconds, while the solder flows into its place.
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Some trial and error may be necessary to get the soldering wire amounts right. If you don’t get cone shapes, and the holes are not fully filled up, that’s too little solder. This can be fixed up by reheating and adding more solder.
If you get balls forming instead of cones, that’s too much solder. This is fixed by either scraping off excess solder using the soldering iron, or using solder wick to absorb and remove the excess solder. Sometimes adding some fresh flux directly or via soldering wire’s core afterwards can help it come to the ideal shape.
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Cool down. Once the solder has flown into shape, rather quickly move the soldering iron out of contact with the pad and pin, and wait a bit until it cools off and solidifies. This can take up to 1-2 seconds (occasionally more, if it was a GND contact with a huge plane, or part of a big metallic part). This is visible visually - the liquid solder is very shiny and reflective, the solid solder looks diffuse.
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Keep track of how long you’ve been at a single spot.
- If it’s taking tens of seconds to get one pin soldered and you don’t succeed, let it cool off and try again later.
- It’s a good idea to jump around between further away contacts, to not get one spot on the PCB too hot. This is relevant when soldering in parts with plastic, which could end up melting if you overheat it at a single spot too much. Or keeping a single pad too hot for too long could make it lift up and break the signal trace contact.
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Keep the tip of your soldering iron clean from excess solder.
- If you see a buildup of solder, or it’s not that ‘fresh’ anymore, wipe it off on the solder iron sponge / mesh, add a tiny amount of fresh solder to the tip, and continue.
This is ended up as a lot of text 
, but the basic principles are quite simple, and should quickly become habit.
Also, YouTube ought to have lots of videos on the subject.
We have some handy tools recommendations on Midiboy’s build guide: Midiboy Assembly Guide – Step 2