Lien laws vary from state to state so you really need to get local advice.
In Florida you should have the GC get separate release of lien's signed by each subcontractor that does major work. Generally your roofer, electrician, HVAC(mechanical), and plumber will cover most work of consequence. The should be made available before the final payment is made to each of them. At the end of the job make sure you have these plus a signed general release of lien from the GC. Make sure they are notarized.
Also make sure you file a "Notice of Commencement" at the start of the job. This is usually required by "Building and Zoning either prior to getting a permit or before the first inspection and is filed at the County Court House. Without it properly and timely filed you cannot enforce the lien laws even if you have the release of liens.