Let's talk about weight loss after 40

I got through a big hurdle this weekend, and my new project is losing some weight. I've watched this subreddit for years, and the vast majority of those who post are in the early 20s.

No offense to those folks, but weight loss is easy at that age. Easier, at any rate.

In my 40s, I have a lot of stress and work that involves sitting down and not a lot of spare time. I have put on a few pounds this last year as I prepared for this thing I had to finish this weekend. My metabolism is like that of a hibernating grizzly bear - partly due to some extreme weight loss I did about 15 years ago. But my metabolism has never been super high.

For those of you over 40:

1. Where did you start?

2. What did you do?

3. What worked for you, and what didn't?

4. How many different "diets" did you try?

5. How important was exercise to you?

Thank you in advance, fellow codgers.

Edit:

I forgot to mention. I don't eat candy or other sweets, including ice cream. I don't drink soft drinks or otherwise drink calories - I drink lots of water and some iced tea. I don't eat chips.