What did you do if you knew you wanted to model something, but didn't know how to make it or just make it look good?
If you're trying to make an accurate model, good reference material will be a big help. Try and find front, top, side and 3D views. If you try to create something just from your imagination or a picture your end result might not be proportioned correctly. Even if you're making something original, try and find something similar and use that for the basic shape.
Also, stick with low-polygon counts to begin with. It will probably help game performance and you can always add details later. Use textures for the finer details -- a 3D artist wouldn't model each individual bump on a basketball, a texture with some texture mapping techniques will do the trick.
Was learning how to 3D model things yourself hard/worth it?
I've still got a lot to learn, but even so, absolutely! Keep in mind you can use 3D modeling for more than just games -- you could make logos, short animations, 3D printing creations, etc.
There are other free 3D modeling programs (like Rocket3F), but the problem with a lot of these is this: While they may be "easier", their communities are usually much smaller too. So if you run into a really obscure bug or issue or don't know how to do something, you may have a hard time getting help. And if you are never able to solve your problem, that could cause you to abandon your project altogether!
Blender sometimes feels like learning a foreign language, but you slowly get used to it. And to use the same analogy, you don't need to be "fluent" in either to accomplish things. If all you have is a firm grasp of the basics that is usually enough to get you started. You don't need 5 years of German to order a pizza. You don't need to become Andrew Price to make a simple donut. And the biggest bonus to using Blender is that so many people use it to some degree that almost any question you can think of has already been answered or could be answered quickly. I get a lot of motivation and inspiration just from seeing all the other cool things people have done with it.