It is not uncommon to be stuck without a strategic resource at least early on in a OCC. The answer there is to build and tech anything that raises your power level. The Great Wall gives you 10k soldiers, if you feel you need more power you can convert a Gspy to a Scotland Yard for 8000 more soldiers rather than settling him, desperate measure but still. The Moai statues is another 10k soldiers..
Go for techs that gives you soldiers.. HBR is another 10k soldiers.. etc.
You have to use diplomacy well in this situation obviously, try to play nice with the aggressive civs and get them to attack other civs.