Waveforms
Most analogue synths are built on the subtractive or analogue synthesis. In it's most basic form it is a three step synthesis form where an oscillator plays a waveform, that is later filtered and then amplified. Different waveforms make different sounds, to understand how to get that certain sound you are looking for you need to know what the different waveforms will do for you.

Sine	The sinewave produces a warm and soft tone, it is often used as a subbass but can also be used for melodic lead parts.	Saw	The sawwave bright and rich sound with strong overtones, this is one of the two waveforms used in the popular 303 synths.
Square	The squarewave has sharp corners, a hollow sound and quite strong overtones. This is one of the two waveforms used in the popular 303 synths.	Triangle	The trianglewave is a mix between the sine and square waves, It's smooth yet with a hollow overtone.
Random	The psychedelic randomwave is the ever changing waveform which can make very odd but useable sounds.	Noise	Noise speaks for itself and can despite it's name make fantastic sounds and noises, one of the perhaps most common uses is making a wind/water like sound.