Lucky for you, forging takes no effort, so you can keep busy with other things. Basically, you start client, unlock account via browser (enter passphrase), close browser with account still unlocked, keep cmd (client) running and you will be forging. You have to keep the client running with your account unlocked for approximately 24 hours for the account to start forging, at which point you will see a notice above the most recent generated block telling you how long until you forge next block.
hmmm no
u don't need to wait 24hrs after you open client for the first time. u need to wait 24hrs after first transaction receveid (1440 confirms), then you can open your client and start forging
My account had Nxt for several days but never forged until I left the client running for 24 hours (1440 confirmations), of course not 24 hours consecutively.