To be attractive to an acquirer, you have to fit into one of their strategic needs. Since acquirers rarely post their strategic needs publicly, you'll often have to guess at what these might be fore your targets.
The best thing to do is look for large, acquisitive buyers who are engaging in active PR in your space, who have made ancillary or adjacent acquisitions to your, and then play the chess game you are able to with your strategy. Numbers, intellectual property, key customers, top talent, growing revenue, are all important to acquirers but not necessarily in that order.
I gave a presentation about the buyer's perspective on M&A back in June to the Seattle Alliance of Angels. You can find it here : https://startup-arts.com/acquisition-buyers-pov/. Knowing the buyer's perspective can help you figure out where you fit in.
I am not a fan of brokers and believe using a broker is akin to shopping your company. I wrote about that topic here : https://startup-arts.com/acquisition-request/