Want to highlight your hair at home? It's basically easy to do without foils or special caps. As long as you choose colors that blend well with your hair and are not a heavy contrast color. That would be very hard to do using this technique.
I have been a licensed Cosmetologist over 19 years. In all those years, I have always used foils or caps to highlight or lowlight. I never knew you didn't need those things if you were using colors that blended well with your hair. I discovered a way to add different colors to my hair quite by accident and decided there and then that this method and technique was way easier than using other methods. Why use caps and foils when you can add color to your hair easily without them?
Of course, you certainly can use foils or caps if you feel better using them. There is no right or wrong way! Whatever method makes you feel the most comfortable is the best way to highlight your hair. I just find that it's easier to add a few here and there, to not use them. Here's how! (This is called the free hand method and also hair painting, which is quite popular overseas! Who knew?)
Remember, if you want to practice using this technique first, you can add some conditioner to your color bottle and experiment placing the color in a line down your section of hair. Smaller sections give you more subtle color. Larger sections give you chunkier highlights.
Highlight your hair around your face to add shine and light up your face. Highlight other sections throughout your hair to add more light to your hair. You can also use slightly darker colors throughout your hair using the same technique. This is called lowlighting and adds dimension to your hair.
Another must-have tip is to only use colors that blend well with your hair. Bleeding of colors can happen using this method, so mistakes will be hidden well, if you stick with colors close to your own hair color. After a few washings however, any bleeding should disappear.