That is a nice base. Now try working in some variations, chips, small cracks, etc. Something to break up the surface - of course not too much, since you want it to tile. Does this have a spec on it, or is it just your diffuse?
Okay, then you need to push your normal more. It isn't doing enough to validate having it at the moment. Your specular is also too shiny at the moment to read as brick. Right now it is making everything look metallic. Nice to see you working color into the diffuse.