The simple answer to how you can promote your company and find and connect with new clients is: social media.
Social networking sites are amazing tools to research key people and news in your industry. The basic social sites you should be "working" to connect with potential clients, keep tabs on industry and competitor doings and expand your brand reach include Twitter, Facebook, Google+ and LinkedIn.
On Twitter and Google+, search hashtagged keywords -- such as #plastics, #plasticsmanufacturing and so on -- to see who is chatting about these topics. Search hashtags of specific product names, industry magazines and events and the names of your competitors too, to discover who is engaging with them. This is a super easy way to discover who is talking about your industry and related products in general, and to identify the folks interested in (and talking about) your specific company and products too.
Once you've identified some great leads, follow those people and the companies they work for, as well as all the trade magazines. Follow your competitors and you'll be able to see who is following and interacting with them. This way you can also keep tabs on their latest news and products.
In terms of promoting your company and products, the key to using social networks is to not to sell, but to add value. Use all your social channels to talk about your industry in general, to be a thought leader, to give tips on how to evaluate your kind of products and to answer the questions that purchasing agents should be asking to help them identify the best company to go with. Share videos and pictures too, as well as some entertaining and (professionally) humorous information and industry event news.
Facebook and Linkedin are excellent resources too, for participating in discussion threads and finding contact details of the buyers in your industry. Niche business networking and listing sites like Vizibility, FastPitch, WomenCentric, Biznik, EntrepreneurConnect and ryze may also yield additional valuable prospect data.
Get started by listening. See how other folks in assorted industries are adding value. You can do the same -- and build brand awareness and sales -- by thoughtfully and strategically engaging new prospects in a variety of social channels.