Most of my work for the past 25 years has been devoted to organizing demonstrations, benefits and campaigns, many of which have had the effect of bringing a policy debate to public focus or moving a political agenda forward. It's become a cliché to say 'think globally and act locally,' but it works.
Sometimes you lose - perhaps because you play against the very best, or because surprises happen - but if there is organizational confidence, you bounce back from losses and convert them to successes.