Is closing a deal solely the responsibility of sales?
I personally think it's not. Sales is everything that starts with brand awareness, the occasional social media touches, and the micro-conversions until it leads to a meaningful conversion—the whole nine yards. This book sums it really well: shorturl.at/rsHR8 Give it an upvote over at ProductHunt main page.
As a sales professional, it is your job to help your company close deals, but you can not do it alone. It would be best if you had a team that could work together to streamline the process from start to finish.