Some sld styles.

Empty star with default marks

For this needed create three point symbolizers with star mark.

    
     
      
       star
       
        #000000
       
      
      18
     
    
    
     
      
       star
       
        #FF0000
       
      
      16
     
    
    
     
      
       star
       
        #FFFFFF
       
      
      10
     
    

All three point symbolizers pretty same, just difference in size and color. But make sure that you put a smallest makr on the top and biggest on down.

Result:

Double dashed line

It's a line dashed with two vertical lines. For this we a needed create three line symbolizers. One with line and two with vertline marks.

    
     
      #00FF00
     
    
    
     
      
       
        
         shape://vertline
         
          #00FF00
          1
         
        
        10
       
      
      10 30
     
    
    
     
      
       
        
         shape://vertline
         
          #00FF00
          1
         
        
        10
       
      
      10 30
      5
     
    

My vertlines is a 1 pixel in width and 10 pixels in lenght. Parameter stroke-dasharray set a distance bitween marks, in my case 30 pixels. Im not sure that clearly know what meen first number 10. Second mark same but with stroke-dashoffset, this paremeter make a offset from the beginning of the line.

Result: