The first place to start practicing is on yourself. This is the one place you can really feel safe to practice, try out new things, and master basic skills. Learn how to blend eye shadow, how to add eye liner (wing eyeliner if your feeling confident), how to apply liquid foundation, how to apply cream foundation, how to add blush, how to conceal pimples and under eyes. Every time you try something new, lay out all the tools and makeup you used to create the look. Snap a picture of your supplies and a selfie, even it it's not great. This is for your own private portfolio, so that you can self critique your learning process. If you are able to, write down all the steps you took and how you liked each product and why. They say the best way to master something is by teaching it, so even if it's just written it will help you understand your application much better.
The next place is family and friends. We all have people that love and support us, this should be a place we feel safe and supported. Don't go apply makeup on the debbie downer friend or a jealous family member. Share your dreams with people that will help keep your dreams afloat. When I started playing with makeup around 17 or so I would make my own clothes and make my little sister "model" for me. This was perfect because she was my little sister she would never say no, what 12 year old isn't going to enjoy dressing up and getting her face painted? So I began practicing on her over and over, quickly realizing how different our face shapes and features were. To this day she is the most difficult winged eyeliner I have ever mastered. I can always do it on the right eye and the left eye just causes me so many problems which I would have never known if I didn't try.
Which brings me to my next point, don't ignore women that are older, overweight, have acne, or are a race your not used to applying makeup on. This is where you will really test your skills as a makeup artist. Dive into it head first! Your grandma came to visit? Cool give her a make over. We all want pictures of makeup on flawless, young, model type skin so we can show off our work but that skin isn't hard to mess up. It's easy to make someone flawless look at least decent, but if you can make grandma look 10 years younger, or someone with a birth mark on their face feel confident about going to a HS reunion, or the senior who went through HS with acne feel beautiful when she goes to prom, that to me is a talented makeup artist.
As far as having a makeup kit be patient, it can take time to build up. When I started I bought a tool box at Wal-mart, when I started actually using it and doing makeup on people I invested in a hard shell makeup case. Eventually I moved onto a fabric nylon makeup case with drawers. Almost 7 years after purchasing my tool box I finally invested in a Zuca Pro and their artist backpack.