The first and most important thing is that the more expensive ships and modules don’t make you better. Experience does that.
Find out what you enjoy doing and learn in cheap ships: the T1 Exploration ships are great, if you lose one then it’ll cost you 5-10m ISK total, and you’ll get that sort of ISK out of a single site in a wormhole, or a good low or nul sec site. Flying Nightmare is not much better than flying an Apocalypse worth a third the price for a Level 4 mission (and the Nightmare has more training to be a better ship).
If you are flying something worth billions then you will be too nervous and worried about the loss. I’m worth tens of billions and I’ll think twice before spending 500m ISK on a ship.
T2 modules are worth it over the Compact/Scoped/Enduring ones, especially T2 weapons and defences. And compared to the Faction and Deadspace modules they are cheap.
T2 ships are about specialisation: they are extremely effective at some tasks, but outside those niches they are expensive liabilities. I use a Triglavian HAC with faction modules for Abyssal sites: but it makes me risk adverse.
So, ISK and stable incomes.
I’d recommend exploration, fit a cheap ship - a Heron since you are Caldari and head into lo-sec or (better) have a look in Wormholes. https://forums.eve-scout.com/topic/409/safety-can-i-warp-to-this-site is handy as a reference (some sites are guarded and the Heron isn’t a fighing ship). Brush up your hacking skills in high sec first if you want, but the rewards are in dangerous places!
Watch d-scan (keep firing it regularly) and keep an eye on what is happening around you. Your heart will race and your holds will fill. Remember: it’s not worth anything until you can get it safe and sold!
That is an area where the T2 ships help, and a T2 frigate - the Buzzard - does help since it has better bonuses and can fit a covert ops cloak (hide with pride!).
I made my ISK through industry: I find all that economics and business management stuff interesting - yep, I’m the one of the “it’s a game of internet spreadsheets” people. Learning T1 industry, making basic stuff to sell is a good starting point and a steady income (drones and ammunition). I mainly specialise in T2 modules and their supply chains. I enjoy it, and I’m lucky that it also gives me a good income - but that comes through experience of what sells and what doesn’t (i.e. what can I make a profit on). That’s hard won knowledge (so don’t ask!!!).
There are many good niches for earning ISK - the obvious easy, boring ones which everyone goes for are not where the money is, rarity, risk and specialisation is where the rewards are.
Importantly: ISK is not a score, and the game is about enjoyment not earning a living. Only fly what you can afford - I’ve lost billion ISK ships (silly overestimation of a situation) and it’s not a nice feeling.