I was fairly serious about improving my handicap when I was younger, then I just started playing for fun. You know get some fresh air, and meet up with a buddy that still likes to golf.
There is this book by Ben Hogan, that really helped me. It's called 5 lessons. It's an oldie but a good book that will improve your golf. I would recommend it. You do not need videos, friends giving advice, or an Instructor. Just follow the easy to follow instructions. It will help.
Putting has always been difficult. The saying you drive for show, putt for dough is so true. If I could solve this, I would be a millionaire. Good luck, Ben Hogan's 5 lessons. You can read it in day, it's not a long read at all. It's 5 lessons. That's all.