The very definition of helpful is "giving or ready to give help." Additionally supported as stating that someone is obliging, eager to please, kind, accommodating, supportive, cooperative; More useful. Synonyms are: useful, of use, beneficial, valuable, profitable, advantageous, fruitful, worthwhile, constructive. The BSA asks all scouters to "do a good turn daily." What does that even mean?
In short, it's everything you'd look for in someone when you need assistance. You want to look for someone who is ready to render aid and who does so with a joyful manner.
Stated differently -- do a good deed daily. BE HELPFUL!