I'm still quite to drawing, around 8 months experience. I'd really like to do some pinup art, in some kind of cartoon flavour. I've been following along with some tutorials, but am finding it hard to pick out what to improve on.
That is a very ambitious goal you've set for yourself! That's a good thing. :)
What sort of basics do you have obtained so far? Have you ever drawn gestures or did you throw yourself at trying to draw realistic portraits right off the bat?
The example you've shown resembles the model quite well, but there are a bunch of issues with the anatomy that tell me you've not fully understood how a face fits together yet. Drawing what you see is a very good practice so definitely keep working on that! But also consider studying anatomy more in-depth, so you understand the proportional relationships between features.
For example, eyes tend to be 1 eye width apart. In the photo you can tell that the space between the corners of her eyes is about 1 eye wide. In your drawing, the space is significantly smaller, which results in the face not looking quite right. Drawing only one line for her nose bridge makes it look a bit off too - half her nose is missing that way! I'd definitely try to draw lines on the left side too, to make it complete.
Does this make sense? Before you go into details learning how to draw features, I think it's a good idea to study proportions first. It will help you tons when you draw what you see to understand how the face it put together. Did you know the tip of the nose lines up with the earlobe? Or that the eyebrows are at about the same height as the tip of the ear? A mouth's corners usually as wide as one inside corner of the eye to the other? :)
Stuff like this is super useful to learn early on as it'll help you drastically in the future when you get to pinups and cartoons. Once you understand how it works, it's really easy to start stylizing.