The correct answer to this open question is the following.
What Juan needs to create a multiracial coalition to the working conditions of migrant workers in the tomato fields of South Florida is to gather enough number of immigrant workers that show unity and solidity of the coalition. Juan also can get in touch with some Hispanic representatives in his area to ask to support the coalition. The coalition could form committees to seriously prepare their demands and support their motives with arguments. This shows they are well prepared and know what they are doing.
There had been cases in Southeast Florida, where coalitions have worked well. That is the case of the Coalition of Immokalee Workers, that on August 12, 2010, signed a Fair Food Code of Conduct with the Pacific Tomato Growers.