Assuming that you have machine A and B in a Windows workgroup. From machine A you want to make remote connection to machine B. 

For PowerShell Remoting to work in a workgroup environment, on both machine A & B, you must first configure your network as a private network, then you must configure the TrustedHosts setting so they will trust each other.  

Machine A

1. Run Windows PowerShell as administrator

2. In the PowerShell console, run the following cmdlets

Set-Item wsman:\localhost\client\trustedhosts *
Restart-Service WinRM
WINRM quickconfig

Machine B

1. Run Windows PowerShell as administrator 

2. In the PowerShell console, run the following cmdlets  

Set-Item wsman:\localhost\client\trustedhosts *
Restart-Service WinRM
WINRM quickconfig

3. In the PowerShell console, run the cmdlet "Enable-PSRemoting -Force"