On top of what other commenters have already mentioned I'd add that it's important not to underestimate the business side of things. Depending on the product an

On top of what other commenters have already mentioned I'd add that it's important not to underestimate the business side of things. Depending on the product and customer, sales could become a massively important topic for your company, basically in all stages... So while it's a good idea to learn the basics, I think at some point you'll need to hire staff to take care of these areas. Depending on the severity of the position and necessary skills these people might ask for shares.