I'll start with a character who has no crafting skills to show how to get from 0 - 400 whilst still making money and to show that it can be done with any of the disciplines I will be picking two at random for her.
To make this easier to keep track of I cancel all my buy bids and throw my remaining item stock at the market cheaply so I can utterly clear the trading post and better track how much money I'm making without being excessive with the maths! Then I grab my guinea pig:
Meet Amber Cunningham, level 6 engineer and utterly average lowbie character (if you ignore the fact I transmuted some pretty clothes to her as I'm an RPer!). I didn't even transfer startup funds to her from an alt as you can see so this is the type of character someone could have on a brand new account in fairly short order. Next I picked her disciplines. To make this utterly random I used random.org's list randomizer and plugged in all of the disciplines and picked the two that came at the top after hitting randomize. And the winners are (drumroll) Jeweler and Huntsman.
My next step was opening 3 tabs up on my browser; GW2Spidy Huntsman, GW2Spidy Jeweler and TPCalc. While the third isn't needed persay GW2Spidy isn't always 100% up to date with the fast moving market and I find it best to have my calculator handy to see if an item is still profitable if it's come down in price a little.
I refine my GW2Spidy pages into level 0-10 recipes and organise by profit:
Now I know it seems like I've stumbled at the starting block on jeweler. Not so, what you need to remember is that GW2Spidy assumes you are buying at the lowest market price rather than placing buy orders. -1c profit looks like it could be turned into a way of breaking even or even a teeny profit. So I take a look at the trading post and see that I can place a buy order at 17c per piece of copper ore, so 34c per ingot - 4 copper less than what GW2Spidy thinks, so I throw the numbers into TPCalc:
Ta da! Potential profit. Now I find myself wishing I'd given myself startup revenue for this project. I can only afford with my meager funds to buy myself a few chunks of ore - so I grab myself 10chunks at 17c, refine them into ingots, list the ingots for 43 copper and now all I can do is wait. There are several ingots listed at 43 so it will take a while for mine to sell but as crafting materials are often bought in bulk I don't mind waiting in line for a while. If I was an actual new character I'd go out and do some questing while I wait for my ingots to sell to earn more money but the whole point of this journal is to show what can be done on crafting alone so instead I hop to an alt to pass the time.
NB: Most people will have more start up revenue than this and will be able to hit the ground running, I just want to show that anybody can do this.