You really need to advertise what types of layouts are your specialty that you can at truthfully state (if not able to physically show due to NDA) that you have done X layouts for Y projects which passed Z compliance/certification/etc testing within # revs - For instance, list how many USB 2.0 or 3.0 layouts done and how many revs were required to pass USB-IF/Apple/etc compliance testing? Or another example, SMPS layout for CISPR 25, achieved certification in X revs (this is a huge one, if you have good layout experience passing CISPR 25 standard you should be able to get lots of work
). Just make sure all statements are truthful, SJ is a small place and once you burn a local player, it tends to follow you
Doing layouts is one thing, but being able to demonstrate that you are capable of creating high quality layouts for specific applications is another. You need to demonstrate your understanding of the specifications that you are advertising for and also show that you can design according to them, with a good understanding of the underlying concepts and/or theories that drive your design choices. I suppose you could also show that you can be supervised by an expert in an application and design under their supervision, if this is something you're doing? If you do these things I think this will get you both more, and larger business opportunities.