Selling: Determine where and how you plan to sell to customers. Consumer product companies, for example, sell to wholesalers who then sell to retailers. In the industrial market, the buying process is longer and involves more decision-makers. You may sell locally, nationally, or even internationally, and some companies only sell their products or services online. Your distribution and sales channels impact who buys your products, when they buy them, and how they buy them.
YouTube has become the second most popular search engine and a lot of users are turning to YouTube before they make a buying decision, to learn something, read a review, or just to relax. There are several video marketing platforms, including Facebook Videos, Instagram, or even TikTok to use to run a video marketing campaign. Companies find the most success with video by integrating it with SEO, content marketing, and broader social media marketing campaigns.
Testimonials. If case studies aren't a good fit for your business, having short testimonials around your website is a good alternative. For B2C brands, think of testimonials a little more loosely. If you're a clothing brand, these might take the form of photos of how other people styled a shirt or dress, pulled from a branded hashtag where people can contribute.
During decline, demand for a good begins to taper off, and the firm may opt to discontinue the manufacture of the product. This is so, if revenue for the product comes from efficiency savings in production, over actual sales of a good/service. However, if a product services a niche market, or is complementary to another product, it may continue the manufacture of the product, despite a low level of sales/revenue being accrued. 
Marketing strategies should ideally have longer lifespans than individual marketing plans because they contain value propositions and other key elements of a company’s brand, which generally hold consistent over the long haul. In other words, marketing strategies cover big-picture messaging, while marketing plans delineate the logistical details of specific campaigns.
As the study of marketing became more prevalent throughout the 20th century, large companies—particularly mass consumer manufacturers—began to recognize the importance of market research, better product design, effective distribution, and sustained communication with consumers in the success of their brands. Marketing concepts and techniques later moved into the industrial-goods sector and subsequently into the services sector. It soon became apparent that organizations and individuals market not only goods and services but also ideas (social marketing), places (location marketing), personalities (celebrity marketing), events (event marketing), and even the organizations themselves (public relations).
Understanding Mobiles: Understanding mobile devices is a significant aspect of digital marketing because smartphones and tablets are now responsible for 64% of the time US consumers are online (Whiteside, 2016). Apps provide a big opportunity as well as challenge for the marketers because firstly the app needs to be downloaded and secondly the person needs to actually use it. This may be difficult as ‘half the time spent on smartphone apps occurs on the individuals single most used app, and almost 85% of their time on the top four rated apps’ (Whiteside, 2016). Mobile advertising can assist in achieving a variety of commercial objectives and it is effective due to taking over the entire screen, and voice or status is likely to be considered highly; although the message must not be seen or thought of as intrusive (Whiteside, 2016). Disadvantages of digital media used on mobile devices also include limited creative capabilities, and reach. Although there are many positive aspects including the users entitlement to select product information, digital media creating a flexible message platform and there is potential for direct selling (Belch & Belch, 2012).
This refers to how the product gets to the customer; the distribution channels and intermediaries such as wholesalers and retailers who enable customers to access products or services in a convenient manner. This third P has also sometimes been called Place or Placement, referring to the channel by which a product or service is sold (e.g. online vs. retail), which geographic region or industry, to which segment (young adults, families, business people), etc. also referring to how the environment in which the product is sold in can affect sales.  5 Digital Marketing Skills to Master for 2020 & Beyond