Best skill to improve your worth to a company

Hi Mike, the best non-STEM skills in a company are likely 1-1 and 1-many communications. Often STEM draws and interests people who are less social, or less "outgoing", while Sales and Marketing roles tend to attract people who are overly social and less likely to have the STEM foundation. In a company, the people who can communicate better and create social bonds are more likely to be advanced, more likely to have opportunities in management, and more likely to have their projects funded and ideas pursued.

For a person with a STEM background, often written communication is easier. It's more precise, and you can put more thought and preparation into it. So mostly I'm recommending verbal communication. However, the ability to write well and effectively convey your message is important as well. Also, being able to convert your idea into a drawing of some kind, both at the detailed and "high level" view, is an important factor in communication. And don't forget listening skills. Remember that the goal of communication is the exchange of information.

An example from my own career came about 10 years ago. I was working with a voice engineer, call him "Fred", who had been promoted to the manager role. He was a fine engineer and very knowledgeable in his area. When speaking with fellow engineers, where he could naturally use technical jargon and references, he felt comfortable and presented himself as more than competent. However, a new CIO came into the company, and Fred felt self-conscious working with unknown people who didn't understand the jargon. He found himself unable to present ideas and solutions in a manner that could be understood, which made the new CIO suspicious of Fred's technical abilities, which of course made Fred more nervous and fed the negative cycle. Fred's group went two years with inadequate budget before he was let go. Fred's inability to communicate not only put bounds on his own career advancement, but it impacted his group as well.

Looking at this from the other side, an engineer who can comfortably speak with people at any level of technical understanding, who can present ideas and solutions to groups of people in a relaxed manner, that engineer has a leg up on people who are socially capable but lack a STEM background. And not only will you be more valuable within the company, you may have opportunities to work with customers or corporate partners and create revenue directly. There are far more opportunities for the engineer, and those types of engineers are far more valuable to a company.

The investment is really just time and practice. There are books, and you might have classes or clubs available to you. Speak to groups in a structured manner where you have to prepare ahead of time. Practice writing down your ideas and thoughts and converting that preparation to speech. Then practice taking your discussions and converting them to writing, even if it's in online forums. Take part in group discussions with all kinds of people, especially non-STEM. Practice meeting and talking to people of all ages, backgrounds, and interests. Even if it's difficult at first, and seems stilted, practice will make it a more natural exercise that becomes part of your personal presentation.

I hope this helps you get started on an enjoyable and profitable career(s).

David had some great recommendations. As a next step, you might want to read some books and other materials. Here are a couple I would recommend to get started:

So Good They Can't Ignore You by Cal Newport (https://www.amazon.com/Good-They-Cant-Ignore-You/dp/1455509124)

This is a great resource on how to make yourself valuable in the field that you work in. It's helped me figure out which skills to focus on at work and really advance my career.

How to Win Friends and Influence People (https://www.amazon.com/How-Win-Friends-Influence-People/dp/0671027034)

This book has been around a long time, but people haven't changed that much. This is a great resource to learn about how best to build relationships and communicate with people so that you can influence them, an important skill in any job.