Not quite OT, I hope, cast iron garden furniture question

I have just bought two little cast iron tables which will live outside
in a sun trap beside a teak bench.  The two tables (coffee mug/wine
glass size) are the wrong colour, painted in a sort of chalky white
which rubs off slightly, and I am planning on painting them glossy
black with an anti-rust specialised paint.  I am just wondering if
people here might have any wisdom as to what preparation I need to do
(beyond usual pre-painting sanding and wiping down), whether it's best
to use distinct anti rust, then special enamel type paint, and
generally what is the best I can do to keep them in good nick outdoors
in all weather?  They're small, so repainting every so often is not an
issue, but I don't want rust stains on clothes after only a few weeks!
Any wisdom much appreciated.

Cat(h)