Convincing moderate Republicans to become Democrats. Recruiting party switchers and supporting their candidacies.
The first thing I would do is address the bleeding in Miami-Dade County. Miami-Dade County went for Trump in 2020, which was a foreteller of the DeSantis victory there in 2022. This would require making direct appeals to Cuban voters in Miami whom the Democrats HAD been making progress with
until 2020. The Gillum campaign was the beginning of the damage; Gillum came off as a Bernie-Bro, and however moderate Miami Cuban Republicans may seem to be, issue-wise, they are NOT moderates on socialism. Palm Beach County needs to be shored up as well, but I believe that the DeSantis victory there was an abberation.
There are counties in FL that, through 2020, were trending Democratic. Duval and Seminole Counties are toss-up counties, and Seminole, definitely, is trending Democratic. There are Republicans upset with the trends; these could be Democratic candidates of 2024. Pinellas County is a third county in this category. St. Lucie is a fourth county; these counties MUST go Democratic for the Democrats to win.
There are other counties that are trending Democratic, but won't carry for the party anytime soon. Lee County (Ft. Myers) is a good example; it's moving toward the Democrats, but Democrats can't win county-wide. What Democrats COULD be doing is electing Democrats in non-partisan races (e. g. Ft. Myers and Cape Coral city commissions). Establish beachheads. Florida has lots of municipalities with non-partisan elections; attempting a stealth effort to get Democrats elected to those positions would be a worthy project. (And I don't mean efforts like the ham-handed attempts to take over school board seats; that didn't go particularly well.)
Biden still won Miami-Dade, it was just a single digit win instead of a blowout like Hillary.