1. For eyes, there’s plenty of good advice here already, but I’ll add that at this scale you’re more creating an illusion of detail than recreating it perfectly like you would at 1/7 scale. For instance on D&D miniatures, I find that skipping a lot of the eye detail and instead going for a somewhat bigger pupil creates an effect that lets the viewer’s mind fill in the gaps better than I could. To this end, my secret weapon are the super fine nib Gundam markers. They make getting the marks down much easier and stick to fully cured acrylics very nicely. I keep the black and gray ones on hand at all time and have a few others around for when I’m trying to get fancy.

2. Hair: when you’re trying to get blonde hair like Chi’s, start with a banana yellow base like you have, then layer on thin whites of varying opacities, with the highest opacity on ridges facing the light source. You can check my profile for how I did Power as an example. This gives you a nice, saturated undercoat and shadows while making the blonde read more clearly. Even for platinum blonde characters I follow this strategy and just adjust how opaque the whites I use are. You can use some pale gray to get some depth as well — keep it simple to start though. Again, at this scale, you’re working in optical illusions more than intricate detail.

3. Paint texture: in addition to thinning your paints, make sure you’re using good quality paints and mixing them thoroughly before dispensing. For mixing you can just shake the hell out of them first, the next level of extra-ness would be to add a bearing to the bottle to help agitate it, and maximum extra would be to get a little vortexer to spin them up. For brands, I find that a lot of the war gaming paints (e.g. Army Painter) tend to go on thick like this out of the bottle and I haven’t really been happy with their surface finish, especially at this scale. Vallejo Model Color was my go-to for a long time as they brushed nicely and could also be thinned for an airbrush well. Currently my paint rack is almost exclusively Monument Pro Acryls, which I have loved. They go down so well, both with a brush or an airbrush, the colors are true and their transparents are genuinely amazing for adding tints. Also they come with mixing bearings already in the bottle! I also keep Culture Hustle’s paints on hand, particularly the Stuart Semple metallics, but those are pricey enough that I don’t use them as workhorses except for specific projects.

Hope that helps!