In article 4556781a$0$81447
,
p says...
I have found that painting the raw cut edge of the drywall with latex paint
increases the adhesion of the mud to these edges and improves the ability to
fill such overcuts around holes, otherwise the mud simply won't stick or
just falls off when dry.

It's also useful to use the mix-it stuff rather than the pre-mixed
mud. The latter turns back to mud when it gets wet by the next
coat'; very frustrating. I use the "90-minute sandable" mix, for
at least the first coat or two.

--
Keith