How can a company use marketing properly?

There are a wide variety of ways that marketing is used. Marketing is much broader than simply advertisements. In encompasses customer insights (learning about your current and potential customers, using data mining and modeling, etc), branding, creative, targeting, social, and many more and evoling areas.

https://www.cleverism.com/understanding-marketing-mix-concept-4ps/

Marketing is anything that falls under the four Ps- promotion, product, price, and place (distribution channel). You can do marketing online, in store, via media channels, in person, etc so it's hard to say that there's one way to do marketing "right", but some main points to consider are:

• Who is your target audience?


• What are their unmet needs that your product or service is solving for?
  -What is the key differentiator or value drivers that set your product/service apart from your competitors?
  -How does your product/serivice uniquely meet those unmet needs in a way no one else can? (your value proposition)

Once you understand the clear value proposition you're trying to communicate, you can choose marketing channels and mediums that best reach the most members of your target audience. Whether it's via social media, traditional advertising, trade publications, events, etc, you just want to make sure the type of marketing vehicle and message aligns with your target consumer and that the avenue/outlet (or venue) is a place where your target consumers are most likely to be to hear your message or connect with your brand.

You have been given some great information already. In my personal experience marketing can and should be leading (or at least part of) the strategic planning process for a company. Market research and customer-led innovation are essential to a company's growth. Strategic marketing is a critical (and sometimes under-utilized) function for a company's success.