Freestyle Technique Images and Video ?

I'm wanting to make slight changes to my freestyle technique/form to work on good mechanics and see if I become more efficient during workouts. Using Google to find visuals for form and technique is overwhelming. I figured USMS forums would be a good place to ask cause this place is a treasure chest of info. Any must-see tutorials? So you know my level: I'm 50, swim 5 days a week, have for about a year now, for fitness, here in Chicago at a 25 yard pool. I generally use a total time and not yardage as my goal for a day. I swim 25-60 minutes per workout. My 50 free time can vary from 42 to 55 depending on how I exert myself. I'm just these past weeks putting flips into my routine to add exertion. Thanks!