OK I'm no guru, this is just what I do.
The only pit contracts I trade are the CME livestock contracts, (and most options are still pit traded)
As all other contacts now have good liquidity, I trade the electronics, so chart those.
Now as to whether to
chart the pit session only or 24 hours, depends on the contract and how much it generally moves out of hours.
These I use 24 hour charts.
Crude Oil
Nat Gas
Gold
T-notes Bonds etc
Currency futures.
All others I only chart the pit session, but I do keep an eye on out of hours movements with audible alarms etc. particularly, grains and NYBOT coffee. This just suits the way I like to trade.
Nothing beats simple observation and learning about each contracts specifications and nuances. Each market is different, has different opening times etc. It's a lot extra to learn over stocks, but that what attracted me in the first place to commods... non-correlation (though be careful there are some correlations between certain markets)
One thing to be careful of is that some contracts are physical delivery such as Gold. This means that at some point before the expiry of the contract, there will be a notice day where you are required to arrange for delivery. Know when this is and be out of that contract and on to the next one.
A simple clue is open interest. About 4 or 5 weeks before expiry you will notice a rapid drop in OI, this is time to consider the next contract if opening a trade, or rolling to the next contract if already in a trade.
Here is the NYBOT Coffee specs for eg:
Good luck