I've got nothing for you on this one. In rec, I put out the message at the initial team meeting about attending and being on time for practice, games. etc. I send out a couple more emails early on as reminders. I ask that they contact me ahead of time to let me know if their child won't be attending on a day and let them know this really helps me plan better.
At higher ages, I try to give more playing time and position preference to kids who make practices/games, put in the time at home, etc. At ages 3/4 and in rec, do your best to make it fun for those who attend.
Travel ball/tournament teams are a different story. You can go all out with contracts, attendance rules, etc.
First, establish the expectation early on with parents. Make it clear that the benefits to their child accrue with repetition, so consistent attendance is important.
Then, provide subtle rewards and reinforcement. Maybe hand out a flyer with drills for the parents to practice with their kids between practices, or announce at one practice what [equipment, experience, attitude] they should bring to the next.
I like Joey's suggestion of rewards/incentives. On hot days I bring a box of popsicles and during practice the kids compete to get the first picks. Also, if you start/end your practices (on time of course) with really fun games, you add motivation to be on time and the kids leave practice looking forward to the next. If you hear things like, "Is practice almost over yet?" it may be time to change gears or refine. Shoot for hearing things like, "One more coach!" "Can we play that one again?" or "Practice is over already?!?" Think about it this way: At this age we want them to have fun and come back next year, and learn a little something about the game along the way. If we can achieve this with a few kids, we're facilitating the love of the game. Hopefully the rest will come along.
well first, try persuading them like this for example:ur kids and hte others will also be having a great time we will practice and take breaks, we will play tag, freeze tag and others. we could do anything, as long as ur kid is in a beutiful and safe invirerment. try telling them that