Better understanding of radio modulation techniques (SDR related)

[Stonent]

I've been playing around with one of those USB DVB TV modules that can be easily used as software defined radio and was trying to better understand some of the transmission types.

I understand AM, FM in general but not so much about upper/lower/dual sidebands, and CW.

I get that upper and lower sidebands seem to move the transmission to just above or below the carrier, and dual is on both sides.  CW I'm not as sure about but it seems to be more for morse code.

When I'm sweeping looking for things with my SDR, is there a point where I need to be changing modes between USB/LSB/DSB and CW?
I know AM is typically used at lower frequencies, and FM more so elsewhere, but not always.  Terrestrial radio in the 86-108MHz band is all wide band FM, but amateur radio seems to be narrow band FM.

Is there a common bandwidth I should be using when looking for radio broadcasts outside commercial radio?

Right now I sweep around looking for the spectrum to move up and down in an area then just play around with LSB/USB/DSB and band widths until I get what sounds the best.

[VK5RC]

I would suggest some reading of something like the ARRL Handbook,  or the RSGB  equivalent,  which will go through it in a well constructed manner,  you can receive CW with SSB,  the tone you hear is the difference between the received Continuous Wave and the suppressed carrier the radio 're-inserts'.