My general advice to businesses is to setup SMART (Specific, Measurable, Achieveable, Realistic, Time scaled) marketing goals. If you haven't established SMART goals before you start marketing, then you probably wont' achieve much (i.e. "I want to increase traffic to my website" is not a SMART goal, neither is "I want to increase sales this year".. A SMART goal would be something like: I want to increase revenue by 25% in the next 12 months). How do you know if your marketing has performed or not if you have no specific goal to benchmark it against?
The first thing you need to decide is how many sales you realistically want to make in the next 12 months. Say you currently have no revenue, but in the next 12 months you want to increase that by £50,000 in revenue. That means you need to generate £50,000 in extra sales with your marketing this year.
A good target to aim with your marketing is a 200% return on investment, so over the next year you'd want to invest £25,000 into your marketing to achieve your goals (a lot of this budget can be spent in terms of your time, if you use an approach similar to the one highlighted at the end of this post). Generally speaking I would avoid marketing in magazines or print, unless you have a big marketing budget, or have a really specific product serving a very small demographic that a particular print publication is extremely good at hitting.
What type of business do you run? My first recommendation to most businesses that don't blog already, is to start. Website's with blogs get ~55% more traffic than websites without, making it an easy and "free" (just your time in writing good posts) method to generate more targeted traffic, providing you keep your blog highly targeted and relevant. You then need to focus on creating a good hook or offer to get people to find out more about your products/services after reading your blog. If you're a B2B business, you could put together a PDF guide for business owners which helps them to solve a pain that's relevant to your product/service. If you run an eCommerce store, then you can put a button to a special offer or package of a few items, or perhaps just a simple blog subscription form.
Once you have a customer's email address, you can send them more helpful material, warm them up and slowly tie in your products/services with their problems more.
If you have a low budget, then you can't really go wrong with things like social media, blogging, engaging with your target demographic on forums, guest posting on relevant blogs, distributing videos, etc.. The only thing you "have" to invest to do all these things is your time, so with my example above, that would be £25,000 of your time.. Which is probably a fair few hours each week on social media/blogging and so forth. Focus on doing a few things very well, though, rather than trying to do everything at once. (you don't need an active social media presence on every single social network, for example).