You can choose to hire people who can help you conceive and then execute strategic marketing plans. However, it you want to have your own pool of marketing people, then you'll need the following to make up your team: a public relations officer, an SEO expert, and a copywriter, among others.
If you hire a marketing consultant, you can gain access to specific marketing skills and experience that you will need to build your business. Hiring a marketing consultant is a more convenient and cost-effective way to have access to marketing expertise.
Marketing to get a bigger market share and maintain it for the long term, is not just a trend.