How do i get rid of rust properly?

Depends what it's on. Small tools and bolts: soak in white vinegar overnight, scrub with steel wool, rinse, then dry immediately and wipe with a bit of oil - skip that last step and it's back in a few days. Bigger stuff like railings or garden furniture: wire brush the loose flakes off, rust converter on what's left, then primer and paint. The paint is what actually stops it returning.