Some tips
Learn one language up to intermediate level first and then start with the new one. It’s best to learn two languages which are very different, instead of something similar like French and Spanish, since you’re highly likely to confuse them.
I recommend doing something like learning Italian and Japanese since they’re so different.
You can also split your time between languages, deciding on one to be your main language and the other one to be the side language. Spend 80% of your time learning Korean and 20% of your time learning Spanish, as an example.
Finally, acknowledge that your speed of learning will be slower in both. Focusing on one gets you faster results, whereas learning two opens more doors but slows down your progress.
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