Truth be told, a tailor doesn't do well until they master for the simple reason that the good colours are all after that final box. But... there are some steps that you can take to make sure you sell well.
#1) Know Thy Customer!! Make what sells. The first order of business is to deal with a product that sells fast. 4 socket items sell well. One thing you should always do is watch before you click item/schematic to see if that thing is 4 socket. 4 socket gloves and belts and shirts will ALWYAS fly off your shelves fast, because people want them for skill tape clothes. When that happens, make a schematic, throw it into your AS friend's factory and churn out a few crates. Put those on your vendor and the bazaar and you'll see how fast they go. Anytime I make a 4 socket item, I check my schematics to see if I need it and choose whether to make a new schematic or not.
#2) Black Sells! The most common colours I get custom requests for is... Colour #4, #91 and #217 (Any tailor should recognize those as Leather Black, Full Colour Black, and Full Colour Scarlet) You might not have the really vibrant colours, but you have black and white, and there is a market for them.
#3) Factory runs. A tailor that can make a full run of synth cloth is an AS's best friend. Put a full 40 crates of identical Synthetic Cloth, Reinforced Fiber Panels andTrim on your vendor. They will sell. Put single factory crates on there too, and the bazaar. I will often be stuck with no synth on me, or I run out of the last jewelry setting, and I will check the bazaar in coronet to see if I can grab a crate. They have a market, and they will sell well
#4) Keep your tag up in starports, cantinas, shuttles, bank areas. Anywhere that people hang out, you can do business. The best thing to tip a new player is a change of clothes. Word of mouth will travel and I do alot of business from "friend of a friend" sales.
#5) Go do some other things as well. Missions, themeparks and checking out poi is one way to feel less despair that the grind is going slow. We all hated the slow crawl up to master. But if you can't grind anymore because your eyes are starting to bleed, then change of scenery!
#6) The bazaar is a great advertisement tool. People will buy stuff and have it on them. They won't ALL look at the clothes' creator to see where to go for a new change of pants, but some will. Don't worry about getting fancy. Sell boots and gloves. New characters get some of the worst shoes imaginable. Those red slippers for entertainers are aweful, and the sneakers are pretty ugly too. Some simple black hide boots (preferably with 4 sockets) will literally FLY off the bazaar. Black gloves will have the same effect.
#7) Get to know the other tailors on your server. If I am too busy, I will recommend others on planets that might be close to the customer. Aimee on Naboo and D'voray on Tatooine are two that I always send people to if I'm on a mission, or an event with friends and have no time. I keep a lengthy list of fellow tailors both in my guild and out of it. Most of them trained from me, and others passed by in a cantina or starport and I just add them to the list.
All in all, the life of a tailor is hard. We are not seen as a NEED by many players because they will never take off their composite. But for a great number of people, tailors are a profession that adds flavour to their characters. I would strongly recommend about 30-60 minutes a day doing some grinding, just to feel that you are making some serious headway in the profession.
Hang in there and enjoy what you're doing.
Jame'thiel Dreamweaver Master Tailor, Colonel - Rebel Alliance, Gorath Server