I have the pleasure of being married to an Electronics Engineer. There are always projects on the go and on many occasions I have to identify components as my eyes are younger and stronger. Along with this, I often have to help with some soldering. I am truly a novice at this, but I do know the basics.
Most importantly, you have to make sure that the soldering iron is at the correct temperature. The solder needs to turn liquid immediately as the two items come in contact with each other. You then place the component in its hole on the circuit board. Just touch on the leg of the component with the soldering iron, which will have a bit of solder on it. This is to hold the component in place. Then you bring the solder to the tip of the soldering iron, and solder all the legs of the component, not applying too much solder as it may cause a short in the circuit.
Another interesting fact is that there are different types of solder. One is lead containing and the other is lead free. The RoHS (Restriction of Hazardous Substances Directive), implemented restrictions on the use of lead containing solder on the 1st July 2006, due to the hazardous gases that are emitted from the lead. Due to the absence of the lead in the solder, it affects the liquid flow when heated. Lead containing solder has a greater surface tension and attaches itself quicker to metal surfaces and flows over the area, whereas lead free solder will attach itself directly to the metal surface with less spread or flow of the liquid solder. Lead free solder also requires a higher temperature than that of lead solder in order to melt.
Solder also comes in different thicknesses, being 1mm, 1.5mm. This is used for ordinary soldering of components onto circuit boards and 0.5mm is used for more delicate soldering such as, hearing aids. There are also two types of soldering, namely through hole soldering, which is usually done by hand. The other is SMT (Surface Mount Technology) which is done by use of SMD (Surface Mount Devices), such us a wave flow machine. Most manufacturers of circuit boards use SMT, due to the mass production requirements, quality requirements and accuracy. Through hole technique is used for most home projects.