Rather than studying specific moves and move orders, you can get away with studying plans and ideas if you're under 2000 FIDE. I got to around 2200 online with

Rather than studying specific moves and move orders, you can get away with studying plans and ideas if you're under 2000 FIDE. I got to around 2200 online with minimal opening memorisation, but with a lot of time dedicated to solving tactical puzzles (2-3 hours every day for around 3 years).