Leveling up Clothing in The Elder Scrolls Online is not a very difficult task but it can be time consuming, especially when you are a new player and you aren't very familiar with how it works, plus you will probably forget about it a few times because there is so much other things to learn in ESO. For an experienced player this takes a few minutes, for a new player this might take a week or two, mostly depending on how many materials that you have available.
Refine raw Materials
While you explore the world of Tamriel in The Elder Scrolls Online you should always pick up any materials that you find. You can then refine these raw materials and gain Inspiration experience while doing so.