The most important thing about buying kids' clothing online is the clothing size, because you cannot try it on, you must confirm the dimensions in order to avoid any trouble caused by incorrect sizing once you receive the clothes. So, please have a flexible measuring tape ready and first measure the chest circumference, clothing length, sleeve length, and pant length of the clothes that fit your baby well. Then decide on the clothing size. Generally speaking, for pure cotton clothing, you can choose a slightly larger size; for tops, you can go up one size, this way they can be worn for a longer time. But pants should not be too long, they should be just the right fit.