Painting Outside

I've been trying to teach myself how to paint outside. Should I go out alone or in a group? What is the best equipment? What are the best materials? Should I sit down or stand up? How to get quiet and concentrate.These are the results of a Saturday trip to the Charles River Peninsula. I spent 2 hours on the first one. I did the second one in the studio with my favorite paper and materials - also about 2 hours. Two different results.