1. Read about soft skills.
2. Classes are good, and some are great. But many are worthless.
3. Observation is required. If you can learn from others mistakes you make fewer, right? Well maybe.
4. Risk a little, and get out of your comfort zone from time to time. In short you do not have to be the hard nose all the time.
5. Be creative, honest, and use humor when you can.
6. Watch your body language and voice inflection.
7. Smile:D:D:D you do not have to fake happiness, but a face full of anger should be reserved for situations that require it. Don't grump at a social event, or when the other team is being recognized.
8. Learn how to leave it. Do not press on in an argument just to prove your point. Smile, say something like, "I don't know about that. But we could discuss that later." and then go on.
Often you prove your point but in doing so you prove to the other person that you are not reasonable, aggressive, dominant, anti them etc... (Don't win the battle at the cost of loosing the war.) Instead of arguing at the table where your flashes of anger and hardness could come out, take the discussion offline and do it later after the emotions have cooled.
9. And above all listen much more then you talk.
Just a few thoughts, after over three decades in the business.
Not all gray hairs are Dinosaurs!