Wash surfaces to be painted with TSP, then scuff (sanding really not needed) the f'glass, wash again with a de-greasing cleaner, paint
a primer /sealer coat with a foam roller and foam disposable brush (to avoid possible lint and bubbles made with a matt type roller). Lightly scuff the primered surfaces (wash/degrease again to get any possible particles or grase from the f'glass) and paint
(with foam roller an brush) with your choice of paint
. There seems to be a few different 'camps' as to which paint is best!! A second (possible) coat could be applied if you decide but there again, I'd lightly scuff down the glass before second coating....
....just my 2 cents worth!!