Learn how to draw curlier hair textures, and do it in the same detail you do straighter hair. If you meticulously draw every strand in straight hair but you draw an afro like a 6-year-old draws a sheep, do better. Make sure you can draw the tightest of curls too. As someone with 4c hair I'm sick of people acting like 3c is the curliest they can depict hair without getting scared.

You can of course give black characters straight hair, but the people are going to need a reason, even if just implied. For example, if your character is a woman who clearly cares about style, you don't have to explicitly state a reason because one can assume she straightened her hair or is wearing a wig for more style points. But in basically any other situation, a black person having straight hair would be odd. Race, after all, is partly defined by phenotype (appearance, a baseline set of shared features), and part of being what someone would call Black is naturally having very curly or kinky hair. If you don't want your character to have that, make them any other race.

Please, please don't desaturate their skin. If you genuinely have a desaturated art style it's fine, just don't lighten their skin in the process. If you claim to have a desaturated art style but your paler characters have clear pink or yellow tones in their skin, you do not have that art style and you are a liar.

Look. You know how you can't draw the collar of a kimono going the wrong way because that's not how Japanese people wear them and it instantly looks fucked up to a Japanese person or anyone familiar with the culture? Well, making your black characters gray looks instantly wrong to a black person. Huge cultural taboo to be gray. So it's not just ugly, it's actively breaking a rule we're all taught at a young age (never be caught ashy or you'll get clowned on).

Draw your black character with the same amount of detail you'd draw a character of any other race in their position of the story. For example: Your average anime character doesn't often have very strong facial features. Big eyes, implied nose, just a line for a closed mouth in your average art style. If you have another main character who's black, or a friendly side character you want to be liked around the same amount, you don't have to add more detail than that. You don't have to draw a big nose, full lips... It's fine, really. Usually main characters in anime are Japanese, who also tend to have wide flat noses and kinda? full lips, or white/white-coded, who tend to have big tall noses and thinner lips, but they don't draw those traits on characters because who cares! It's not about being accurate to reality! It's about being cute!!!!!!!!! Characters are only drawn with racialized features (or any strong features at all) when they're not important, the point is their foreigness, or they're not supposed to be attractive. You should apply the same logic to black characters.

Thusly, any other tip you hear about drawing black people when you're a weeb isn't as important. Wide nose? Big two-toned lips? High cheekbones? Lighter palms and soles? Nope, you don't need to worry about any of that. If you don't usually draw in such detail, you don't have to start now.