Soldering is Easy
The most common mistakes when soldering are.. Trying to apply heat to the solder directly.
We heat the parts making a connection, and feed solder under it. Forgetting to tin cable ends and connector tips before soldering.
When you strip a cable, tin it, when you need to join a contact (switch, meter terminal etc), tin it - that way, youll make a nice connection.
If you have doubts, there are tons of guides on youtube.. Happy soldering!