Tom, definitely make it easy for people to contact you, you never know when it might make the difference between a sale or not.
People's ideas whether or not they are likely customers are great inspiration for practice projects, i do that all the time.
And yes it's always worth pushing you skills even if there's not a customer on the other end of the job.
FYI i'm in a very similar position to you, just maybe a few months further along, i too have a day job and am currently getting tooled up and pulling in commissions where possible.