How about this:
Is pleasant and friendly, says hello and attempts to build a good relationship with me (the teacher).
Asks questions if they are worried or confused - doesn't leap to conclusions or sit on a worry for months.
Hears their child read, at least occasionally.
Speaks kindly to their child, comes to plays, parents evening etc.
Encourages and looks out for their child, but also has the insight to see that other children need a chance too (re parts in plays etc)
Volunteers to help, and is not too fussy about the job given, eg would be happy to wash up paint pots or take a display off the wall.
After volunteering, does not gossip to other parents about what they have seen / heard in the classroom. Respects confidences.
Does not think their child is an angel / blameless in every situation, but will back school up in disciplinary situations. Realises that teachers have no interest in 'picking on' your child
Says thank you to the teacher for things 'above and beyond' - if you want to be loved by your child's teacher this is the easiest one by far!
And yes, maybe gives alcohol at Christmas!