Best Modeling Exercises?

I am an intermediate Blender user and I am realizing that tutorials are no longer helpful to me and I need to just start practicing, Sometimes when I practice I can make something a lot better than I thought I could like a model of Raptor but if I do something similar like a Trex I can’t get past turning the traced primitive polygon into a 3d body with depth. I can make some models not half bad like a portal gun from Portal or a Velociraptor but other things like Realistic Grass, Rexs, Frogs (The legs is the part that confuses me), ivy (for games), bi-peds, etc are a huge struggle for me. I want to start from the ground up and eventually work myself into sculpting and retopo so, what are some practices I can do to grow as a 3D Modeler? Again I am very familiar with Blender that isn’t my problem my problem is I don’t know how to tell what models are too difficult or too hard for my skill level.

For organic modeling, you really need to practice your eye for scale and proportion.
practice drawing with a pencil and paper to hone your eye and get a better sense of what you are trying to model.

Hard surface modeling also needs those same skills, but you can cheat a little more. I recommend modeling a real object you have. You can measure the object to make sure everything is in scale and appropriately proportioned. It’s way harder to measure a T-rex, haha.

Thanks this really helped! I will try it, one question though, I do have a graphics tablet I’m trying to adjust to, do you think I could use this instead of traditional pen and paper? Thank you!

I think doing it on paper will make it easier to do it digitally, but practice both. You can sketch anywhere, you can only use your tablet when you are at your computer.

Working with a 2d medium gives you a different lens to understand the shape of things.