Commodities' demand generally remains fixed across systems and does not dynamically change as you buy and sell stuff. So trading is a great way to build up some credit flow especially in the beginning to afford your first ship

Systems are in order of discovery through progression. Commodities are ordered alphabetically. Demand statuses are taken from the inventory whilst in supralight space. If you have space to spare in your cargo, buy low and sell high where you can. The greater the commodity rarity, the higher your profit will be.

• When you first arrive at Prescott Base to look for Maddocks, you have to visit all the ramen shops. It's a good time to stock up on a load of cheap ramen to sell as soon as you go back to Ceto.
  
  
• Try to beeline HIVE's Autonomous Cargo Dispatcher perk upgrade as it allows you to remotely send cargo from your ship to your homebase. I ended up using this to send a load of Earth Wine & Mining Equipment to my base and stopping by to pick up & sell once its storage space was full
  
  
• Eventually you will get access to the ability to instantly fast travel between systems without using jumpgates via the main story but that will take 25-30 hours.

Please comment any other helpful tips you can think of! Thanks for reading!