We are small IT outsource company located in Ukraine (but registered in USA). We have clients over the world. We are working like dedicated team, for existed projects who need cost effective resources.
We need to get to new level : create bigger solutions for bigger clients. For now we get projects from be references and sometimes from: elance and odesk. We do not have any sales and finance managers, just team of developers. We'd like to work as simple as possible.
What is the best but simple steps to get to our goal?
As a programmer this is the last answer you want to here, but it's what you need to do.
Start learning about how to do advertising, marketing and sales. You or someone in your business is going to have to sell and make deals with businesses. This may be you, someone else in your company, or someone you need to hire to help with these efforts.
Since you have been doing work for some companies already, have you learned anything specific about a business industry? Have you delivered multiple solutions for a specific industry?
It's easiest to market and sell to businesses if you have a specific niche. This may be some industry experience, some technology you are experts at, or some magic sauce that makes you better than another company someone may hire.
You need to find out what that is, or what that can be and then work on selling and marketing that.
Even if you are doing general consulting and you have the coding skills to build whatever a customer may want - it helps to find a niche. It makes it easier to sell and relate to your customers. Once you find your angle, you then have to start advertising, marketing and selling.
There are a hundreds of options, and from your question there is no quick fix, or one thing to do. The realization you have to come to is that you now run a business and that there is more to that then coding.
I would start picking up some books to help you accelerate your learning and to start thinking about what else you need to be doing with your business.
Here are a couple initial book suggestions.
When I started my business I didn't really think about these types of things and had to learn quickly about sales, marketing and all the other things that go into running a business.
Also, as a consulting company it's very difficult to just start working with the biggest clients and biggest projects. Those are the clients least likely to take risk and most likely to have money to pay for top consultants. If you don't have a strong portfolio, proven successes, great marketing and sales strategy it will be difficult to acquire those clients and projects.
Although not the easy answer you wanted, this will serve you better ;)
You know how to build software. At the moment, you're building software for others and you're in the IT outsourcing business.
Build a software for yourself; build an online business that generates revenue.