Watch the video above if you want to see some easy ways to paint rust with Games Workshops paints. In this video I am just using Typhus Corrosion and a couple of browns to drybrush over that to make rust.
It’s very easy to get a good rust look with just a handful of paints. On smaller models like Necron warriors, I probably wouldn’t even bother with the browns and just go for Typhus Corrosion and Ryza Rust. That speeds up painting 20 warrior blocks significantly.
More elaborate rust effects with AK Interactive
You can get more elaborate, different and more realistic looking rust with enamel paints. If that’s what you are looking for, then I recommend you watch my video where I paint my Death Guard Plague Burst Crawler here.
In that video I paint the rust exclusively with AK rust paints, such as Crusted Rust Deposits and Rust Streaks. This is a bit more advanced, since you need to get white spirits to water down your paints and you need to have some decent brush control to get the results you want.
Still, I would say enamel paints like Streaking Grime and Rust Streaks should be your next step once you learn to paint minis to a decent level.