The only things that work reliably here are hard work marketing the company and its capability to solve customer problems; and being a specialized provider and identified closely with a particular area of expertise. Yes to everything you said as a technique.
Just be aware that with active techniques like cold calling, you absolutely must have a valuable immediate proposition or solution for the target, or else the call ends up sounding like spam. It can and does work. It requires research and affinity with the target prospects to do properly.
Here's my brutal assessment of the vast majority of RFPs (requests for proposals) and their authors on freelancing sites.
The core problem with freelancing sites is that the RFPs almost always come from product companies or startups, and the needs virtually never involve a paying end client who has a pressing need to solve. The needs virtually never come from end users - where you make the most money solving line of business problems.
Freelancing sites are for "staff augmentation" at both a micro scale and at a micro fee level. So this means that 95+% of these posted opportunities come from unfinanced hobby or side businesses, dreamers, and insolvent wanna-bes. In almost every case, you are sending your bid to another programmer, or to someone with a dream about a particular application or product idea, who has very strict ideas about what the resource should cost - and those ideas of cost center on "as low as possible."
My experience has been that the junk to good stuff ratio on these boards generally tops 10:1. I mean that for every reasonably well stated project with reasonable expectations, there are 9 that are stupid or ill-considered. The scale of the work generally requested on these sites, and the money involved screams "unimportance".
Based on the way you stated your question, you're ready to move up. Direct marketing to end users is the next logical step to take.