From what I've been able to gather, these were the major problems Bernie had in obtaining POC votes

[TheKentuckian]

26. There is no such thing as swiftboat proof and brand recognition is a tall hill

The Sanders campaign wasn't perfect or even top shelf but it wasn't awful, it did not come out specifically and directly campaigning for the black vote and I'm not sure it could and other than very local campaigns I've not seen it happen including Clinton's but it may have been the only way to get even ground with that particular swiftboat and brand advantage.

Moving forward? Get into the churches and get some money moving. Lay some foundation with Urban Leagues.

I'd say some of the business cliques, foundations, and groups and I guess you have to try because a lot of those folks have huge influence but it is always uphill dealing with the money focused minority status isn't an immunity shield to greed and "I built this", make no mistake if the TeaPubLieKlans weren't a bunch racist dumpster fires a bunch of folks would be STAUNCH Republicans (and a few actually are anyway).
Some black Democrats are actually both fiscal and socially conservative, we hold them because we don't oppose their humanity they aren't going too liberal if they can help it.

Build networks with black educators.

More are kind of socially conservative and moderate or even liberal fiscally and even more are moderate/non ideological but are fiercely partisan out of necessity these folks are risk adverse because they or people they love are in precarious positions disruptions hit them first and hardest as do Republican wins so functionally they are allied with the status quo, you got to convince them you are as safe a bet or better than the establishment candidate.

Mission critical though is engaging young minority voters and getting them to turn out and do it consistently. Gotta nip the establishment comfort and conservatism in the bud and grow liberalism.

You have to build relationships and be a familiar.

It's tough against the Clintons (though it shouldn't be, I think we should be running scared when they come glad handing and clapping because the next fuck over is coming) but a lot of black folks put a lot into they come to sell them on the screwing first and transfer the blame to generic white liberals peddling snake (amnesia sets in who the white Democrats were it seems) oil later once the reaming is clear.
I'm like that "relationship" y'all are going about was those not actually liberal white politicians selling us the fuck out with shit like the crime bill and education deform.
That rising tide that failed to lift all ships? The same motherfuckers were Pied Pipering that shit to beat the band and managed to somehow hang it on liberals too.

You can't sell and close on policy without the networking is all I can pull out of it. Strangely, you might have the patience to make more sense out of it than me because my brain says "does not compute" in many sections, I don't feel inside on this