Space trucking is a hybrid of station trading and hauling. It can be pretty profitable if you are market-savy and have a few junk alts hanging around. I did a great deal of space trucking. I had pretty good results, but it takes a special person to move goods from stations to trade hubs, trade hubs to stations and/or trade hubs to trade hubs. It can be boring as all hell, especially if you are doing it in a freighter.
You don't have to have a huge stockpile of ISK to start, nor do you have to invest a lot into your logistics. A T1 hauler with cargo expanders (and some tank modules) is plenty to move goods around. If you are hauling massive amounts of goods, you might want to have a freighter or a max cargo fit T1 industrial. If you want to specialist in some particular item type, you can pick an industrial with cargo holds specific to that item. For example, if you are going to focus on planetary interaction goods, I would suggest getting an Epithal instead of a Mammoth due to the Epithal's planetary commodity bay. Sometimes doing multiple trips in a industrial is more productive than doing one large trip in a freighter. With freighters getting rigs very soon, you might find you are better off with a freighter.
What I suggest is going from trade hub to trade hub (if you have a lot of time) or gathering goods at NPC mission hubs and returning the goods to the closest market hub. An example is Auvergne to Dodixie (where Auvergne is the mission hub). Auvergne is a Federation Intel level 4 mission hub. Mission runners might not want to waste their time hauling goods to Dodixie and often just put up their goods in Auv. for less than what you can sell them to buy orders in Dodixie. That is what we call a 'trade opportunity'.
If you are planning to enter this profession, you will need every advantage you can possibly get. This is why I suggest installing a few alts in the trade hubs. You should have one alt in each of the stations you wish to trade to and from. For example, I still have an alt in Dodixie, Amarr and Jita. This way you can check for the current buy and sell price in both stations. The worst thing you can do is trade on old/outdated information. That is a gamble and very easy to lose.
The next thing you want to do is get your butt over to EVE Central. You can install the Contributastic app and participate in helping gather market intelligence. You then use the trade tools on the site to check out trade routes. Once you know what items are being traded for a profit, you can then use your market alts to verify them BEFORE you buy the goods.
|EVE Central's Trade Route finder|
You have to consider all the costs and deduct them form the item sale. Don't forget to include tax and market fees or you could lose your margin or sell below cost. Two things that will have a negative impact on your career and profits. If you have any questions, leave them in the comments and as always, fly safe-ish.