I found starting with vocabulary the most effective. take A1 vocabulary lists, and make memorization a daily routine. 

if the grammar of your target language is similar to a language you already speak, ignore it for now. if you need some grammar for comprehension, focus only on that. so don’t waste time (yet) on gender or case systems. 

if you manage to stay dedicated, you can start reading and listening surprisingly quickly. ofc it should be either easy texts and audio, or stuff you’ve already familiar with. 

other tips: don’t get frustrated by quitting, accept the break and start again; if you’re bored with one specific activity, switch it up. you need to practice listening, reading, writing, grammar, speaking, etc anyways; and if you don’t manage to motivate yourself, pay someone to do it for you (if you have the means ofc). 

it’s probably not universal, but this worked for me.