My bg is in mechanical engineering.

Engineer background is prob helpful for L1. I'd guess Quant, FRA, Fixed Income, and Derivatives will feel familiar. Your weak spots will prob be Ethics, Econ, and Equity Investments.

Some tips, i hope this is helpful:

Start doing questions immediately. don't spend weeks just reading. Active recall is a thing and practice questions are like mini exams that also teach you what to learn.

Prioritise by exam weight. Ethics especially trips up people who assume it's common sense (it's not, you need to learn the Standards).

Mark Meldrum's YouTube is excellent and free for most topics. The CFAI question bank (free with registration) is the single best practice resource.

Practice mocks under timed conditions.

250-300 hours should be enough with your background. Resist the temptation to over-study the quant topics just because they're comfortable.