websites:

• talktomeinkorean (useful for vocab!)
• (they also have a soundcloud with audio lessons!)
• howtostudykorean
• memrise (very useful for self-study!)
• naver translate (my go-to)
• a very useful dictionary!

books:

• korean from zero (free online!)
• korean grammar in use (beginner, intermediate, advanced)
• ewha korean
• korean for beginners (focused on actual sentences rather than grammar, useful for fast-paced speaking abilities!)
• korean made simple (recently started using this series and it's really good!! really in-depth explanations)

general advice:

• learn how to read/write 한글! it can seem pretty scary at first, but it's actually one of the most simple writing systems you could ever master! not depending on romanization and being able to pronounce korean words properly will really help you. plus. it looks cool!
• afterwards, build on those skills by first studying the basic grammatical concepts (such as particles, sentence structure and conjugating verbs) and then by beginning to add new words to your vocabulary! the grammar part of korean is actually not that difficult; once you learn that, you will be able to say anything. but you have to know how to say it, and so, vocabulary comes into play! in my opinion, that's what's actually the hardest - there are very many words to learn, and some of them even have 2 to 3 meanings!
• what has really helped me is trying to relate grammatical concepts/new words to songs! for example, if i ever forgot the word for 'blood', i could just think of bangtan's song '피 땀 눈물' and i'm good!
• think of what sentences you would personally say/use the most, and then translate them using a reliable source! it'll help with sentence structure and also new words that will immediately stick to your brain!
• to put it simply, literally google anything and everything! this holds true not only for learning korean, but just in general! we have tons of resources at our disposal in this day and age - use them to your advantage!
• practice! i know this is generic advice, but it's honestly so important! study every day, try using hellotalk to improve by chatting with native korean speakers, or just try keeping a diary and writing 5-10 sentences in korean each day! you'll be amazed by your progress in a few months!