Levi Strauss created the very first pair of jeans in 1853. Since then, the brand has expanded to include numerous different types and brands of jeans (including the iconic 501s) and other clothing apparel. Jeans these days come in a number of different cuts and styles. Despite the numerous jean offerings, your Levis may not fit exactly how you'd like them. Perhaps they are simply to loose due to constant wear, or perhaps the stock skinny jean just doesn't come tight enough--regardless, there a few ways you can customise your Levi jeans.
Put the jeans in the washer. After the wash cycle, place the jeans in a long, dry cycle on the hottest setting. The jeans should remain in the dryer longer than normally necessary in order to shrink them, versus simply dry them. If you are able, run the dry cycle twice. After completion, the jeans should fit tighter.
Turn the jeans inside out. Use a sewing machine to take in the inner leg seams. Before turning them inside, put the jeans on and use pins to determine where to sew the new inseam - you do not want them to be too tight that you can't put them on.
Take the jeans to a tailor or seamstress. Work with her to determine your desired fit for the Levis. It will not be as cost-effective as placing them in the dryer or sewing the jeans yourself, but the overall result is a better fitting, tighter jean.