Know your rights. Often, the management at a business will try to discourage employees from forming a union, as union workers usually get higher pay and better working conditions than non-union workers. It's important to know your legal rights when it comes to forming a union so you can protect yourself and, if necessary, fight back against any illegal action by your employer.
In the US, the National Labor Relations Act (NLRA) details the rights of union members as well as would-be union members. Most courts have decided the Section 7 of the NLRA dictates the following legal mandates:
Employees may discuss the idea of forming a union and distribute union literature during non-work time and in non-work places - like, for instance, a break room. They may also display their union support through clothing, pins, jewelry, etc.
Employees can ask other employees to sign petitions regarding the formation of a union, specific employment grievances, etc. Employees can also ask employers to recognize these petitions.
Additionally, most courts agree that Section 8 of the NLRA provides the following protections:
Employers cannot offer raises, promotions, or other incentives to employees if they agree not to unionize.
Employers cannot close down a work site or otherwise transfer work away from certain employees because of union affiliation.
Employers cannot fire, demote, harass, dock pay from, or otherwise punish employees because of union affiliation.
Finally, employers also cannot threaten to do any of the above acts.