Start with the one-dropper loop
Your base begins with one dropper and grows through upgraders. Collect its output, buy the next useful upgrade, and use each unlock to open another way to make money.
Build around the next unlock
Do not spend just because a button is available. Prioritize the purchase that unlocks a new income route or makes the current dropper chain pay out more consistently.
Use the leaderboard as a long-term goal
The official description frames reaching the top of the leaderboards as an end goal. Treat it as a reason to keep improving your base, not as a shortcut past the normal progression loop.