Having built VR/AR applications for a long time, I have seen a lot of folks struggle to get into the industry and it does take time and a lot of perseverance. The most successful common route I have done and seen others do, are based on strength of portfolio examples:
For media agencies you will usually need two examples of a product configurator e.g car you can change colors, materials etc and a basic game example is a bonus.
For training organisations you will need a basic part task trainer e.g. dissassemble/assembly a complex part or piece of equipment and step through each part task
For engineering design viz - start with a complex piece of CAD data, optimize it and show in both desktop and VR - and had a good demo quirk - such as interactive annotations or highlighting sequences etc and be prepared to be able to talk through the how you made it steps at each point (especially the optimization from CAD stage)
For architectural viz - a real time walk through showing off lighting and shader capabilities and interactive walk through where you click on things to get more info.
For data visualization - obviously a data visualization example doing this well is harder than it first appears but see http://bit.ly/2yb5ZvC for inspiration.
Build which ever example of the above is closest to the type of work you want to do, then create a portfolio website showing off your examples so you can send prospects a link to see a video of your work.
Then use linkedin and google to find your target companies in the area you want to work. For example look for -
Marketing - Media director / producer in a media agency, also do a search for '3D, Virtual Reality and Augmented Reality solutions for businesses' that will find a lot of the specialized contractors
Training Organisation - Head of training in a defense contractors/equipment manufacturers / industrial training organisations
Engineering Design - Design Visualization Manager in product manufacturer of your choice e.g. Automotive, Aerospace, industrial equipment etc.
Arch Viz - specialist architectural Viz firms or very big architecture firms (who have arch viz in house)
Data Viz - do a linkedin and google search for Interactive data visualization exhibits - it will find a good cross section of those working in this area
Then its like any sales - cold contact and its a numbers game till you get interest.
Last but not least a number of agencies use places like UpWork and remoteok to find contractors. A couple of such projects done at a lower cost can help you get experience when you start out and can help make a resume and portfolio standout as you go for bigger gigs.
Good luck!