I have for years! I record myself with my computer, or my portable recorder, or even my cell phone and play it back and listen to it.
Sometimes I record just me, other times I record with the music in the background at just the right volume so my voice blends then I can see where I am off more easily.
Also, using a pitch pipe I can practice hitting notes, doing scales.
It helps to get lots and lots of exercise for your lungs, your mouth, your throat, your lips...
Everything.
Through practice alone you can learn to identify where certain notes come from, like higher stuff tends to resonate in the nasal cavity, and lower stuff can resonate in the lungs and diaphragm.
Sing as much as possible, every day!
I installed a powerful stereo in my truck so I would have to sing loud to compete with it.
I bought a good mixer and quality microphone, and also a cardioid microphone with a shock absorber mount. Stands. And great quality speakers for my computer. Plus a good sound card.
It all adds up over time.
Also, Singing for Dummies isn't bad.
The book store actually has quite a few books to read on vocal instruction.
Lastly, if you're religious, join a church choir or vocal ensemble. Look for any programs at your school.
Don't be afraid! The voice is an instrument just like a guitar or piano.
Learn to use it well and you'll have nothing to be ashamed of!