Follow a few guides to get the hang of the sphere grid. Your first few characters will be throwaways so get used to that now
- and start saving all the currency you can get on each of those characters. ****ing HOARD anything and store it for future use, including yellow items. When you decide to re-roll you'll thank me later!
Find what style you enjoy playing as and follow it and improve on it. If you like theorycrafting (like me) you'll enjoy the spheregrid a lot.
So many guides on the basics of PoE that I'd recommend going through, too much to explain really. As long as you're enjoying yourself doesn't really matter.