Good Info graph below depicting future Internet trends. Mobile ads set to grow with more budgets for marketing on FB . Twitter YouTube also to grow as marketing channels.
Social media marketing , Search engine marketing (PPC,Adwords, SEO), Email marketing , Mobile marketing ,Content marketing , affiliate marketing and using your mobile responsive website as the face of your business online with inbound marketing efforts.
Above needs to be integrated to your overall 360 degree communication plan covering Above the line and Below the line efforts.
Further focus on customer Data is also key to carry out data driven marketing efforts. You need to have a relevant and effective customer relationship management tool capturing data from all customer touch points.
In order to effectively carry out above , business needs to have a well trained passionate in house team that can co-create and collaborate with external agencies in order to develop and carry out strategies based on overall business objectives.
You could also read my older blogs on importance of a website and basic mistakes made on social media marketing.