First thing first, the EVE market is the place where you can buy and sell most of goods. Some items can not be listed on the market and are sold on escrow. The market screen allows you to sort by the number of jumps from you an items is, the volume, cost, location and so on. Make sure that you buy eve isk , you have not bought region/system wide" if you didn't want to. There are 2/3 options available to you for your search "scope", how far away you want to look from where you are. There is also an often over looked but very useful history tab, that will tell you the price and volume of an item over varying amounts of time.
Of note, the market supply and demand now changes with every buy and sell order processed. When you sell something to an NPC the demand price "usually" goes down, as the orders are filled. And the buy eve isk price goes up as more is purchased. The temptation is to deliver and sell, deliver and sell, completing the demand at a station, but doing this will leave some profit behind, as the price changes with every transaction, "most of the time". So get it all there first, and sell it together, buy the same way, all at once.
By now you should have the idea of the importance of skill. The starship skills you have chosen should meet the goals you have set for the types of delivery ships you wish to use and you should be on your eve isk way to a "bigger" Industrial. Now we are going to focus on the ability to make use of trade skills or utmost advantages. Probably you have notices that you are getting socked with a hefty sales tax and broker fees. It is the time for you to get marketing, broker relations, and Accounting. Broker relations and accounting will decrease the fees you pay when you place a buy order for items not yet listed to sell, and the tax for each and every sale you make.