Repeaters transmit between channels 1-8 and receive between channels 31 and 38.  Avoid these channels for non-repeater (simplex) communications.   Repeaters operating on Channel 5/35 may be used for emergency communication only.  If you have 'line of sight' communication, you should move from the repeater to a simplex channel to leave the repeater channel free for others who cannot communicate direct. 

Channels 22 and 23 are used for telemetry and remote control purposed. Voice communications on these channels is not allowed.

Channel 11 is the call channel, most people use repeaters for this purpose instead.  Many truck drivers use Channel 40. 

These channels are recommended for general simplex communication:  9, 10, 12-21, 23-30, 39.