Illustrator is difficult to learn, but it's the ideal tool for advanced work.
Learning the path tools and keyboard shortcuts is absolutely critical to working efficiently in illustrator.
Tutorials are very helpful for learning intermediate concepts, such as how and when to use blends and gradients, and developing efficient path construction techniques.
A good exercise for learning the path tools would be to draw an accurate path around a complex object, such as a ferris wheel or other object with lots of holes, curves and details. Once you can do this, everything else will come easy.