CSS! Firefox with Firebug will come in handy.
SEAM-gen'd forms use a single column layout. You can easily add more columns by wrapping them in <div> elements and applying proper styles. Search about CSS layouts, form CSS layouts, there are plenty of resources.
How do i increase the width of the labels generated by seam-gen, i have tried changing values in theme.css like the classes name, value etc but it didn't work. I tried looking for the div class prop but could not locate it in the css. My labels need longer text
changing values in theme.css like the classes name, value etc is Correct !!!, only that the server just needs a restart for the changes to take effect. Simply increase the class name to increase width of labels, and class values for the the value controls on the right side of the labels e.g. textboxes etc.
The problem is just restarting the server, having to go offline etc, it should be a chching problem i think, hope it helps