Relevancy is the first qualifier of a quality link opportunity. The next qualifying factor is the authority of the opportunity. Since Google doesn’t update PageRank (PR) anymore, you must rely on third party metrics. I recommend you use Domain Authority (DA) from Open Site Explorer, Domain Rate (DR) from Ahrefs, or Trust Flow from Majestic to determine the quality of your link opportunities. You should use all three tools if you can.
Influencers: Government Contracting Officers, Other GovCon (Government Contracting) consultants, Sellers of professional services for small businesses (certain CPAs, bonding companies, financial institutions, contract attorneys), large contracting firms (who need to hire small business subcontractors), Union/trade organizations, Construction and Engineering trade publications
Search engines use complex mathematical algorithms to interpret which websites a user seeks. In this diagram, if each bubble represents a website, programs sometimes called spiders examine which sites link to which other sites, with arrows representing these links. Websites getting more inbound links, or stronger links, are presumed to be more important and what the user is searching for. In this example, since website B is the recipient of numerous inbound links, it ranks more highly in a web search. And the links "carry through", such that website C, even though it only has one inbound link, has an inbound link from a highly popular site (B) while site E does not. Note: Percentages are rounded.
Lastly, it's important to remember that paralysis by over-thinking is a real issue some struggle with. There's no pill for it (yet). Predicting perfection is a fool's errand. Get as close as you can within a reasonable timeframe, and prepare for future iteration. If you're traveling through your plan and determine a soft spot at any time, simply pivot. It's many hours of upfront work to get your strategy built, but it's not too hard to tweak as you go.