At first, stick to the basic sidewinder. Don't bother upgrading it for now (except for a bigger cargo rack) when you die, you get a FREE basic sidey. DO NOT sell your Basic Discovery Scanner.
Go to Lave, and also check out the nearby systems. you're looking for Rare Commodities. They're easy to spot in the Market screen: They're a different colour.
Buy as much as you can, then pick any direction and fly 160 LY, scanning unexplored systems as you go. Then sell your cargo for a MASSIVE profit. Also sell your Cartographic data for free money. Rinse and repeat. Find more systems selling Rare Commodities (Hint: There's a thread with a fairly complete list). Find 2 "hubs" with a few Rare Commodities sellers close to each other, over 160LY apart and go back and forth, scanning as you go.
Do some missions, go to some combat zones (with an empty cargo hold!), submit to NPC interdictions (PC's will probably blow you to dust if you fight back in a sidey), stop at USS's.
When you can afford a hauler, earn twice as many credits again before you buy it, upgrade the FSD, thrusters, shields and cargo racks, and carry on with 4 times the cargo space you had in the sidey.
Rinse and repeat. Your next ship should be a Cobra.
Now you're a Player.
At 5 hours a day, if it takes you more than 2 or 3 days, rethink your sterategy/routes.