Marketing is a huge part of making any business a success. Depending on what size your company is, the industry you are in and your target audience will have an impact on what avenues of marketing you go for and how much you budget for each of these.
Online marketing is fast over taking offline marketing, and although some companies do both (which is ideal) there are far too many companies out there that are still only advertising in their local paper or magazine and in the Yellow pages.
If you do not actively market online then I would suggest getting in to with a digital agency who will be able to assist you with your marketing requirements. They will have a wealth of experiences and resources to hand to allow them to promote your company across new platforms you may have never tried before. Do not just expect the work to come to you, not advertising is a risky strategy and the work normally soon dries up.