Enthusiasm is important and this can come from things like admiration for the culture and history or romantic associations. It is also important to feel the rhythm and sound of the language. Some languages can be quite musical in their flow and pronunciation. Secondly, carefully consider problems with pronunciation. It's always better to have a native teach you and better still to live in the country itself while learning.
Correct pronunciation is essential.
For Westerners, Asian languages can present big pronunciation problems and the same applies for Asians learning Western languages. This is because the mouth and tongue are often utilised differently in pronunciation. Thirdly, it is necessary to make a brief study of the grammatical construction of a language. Just a basic understanding is enough. Fourthly, make a list of essential words to get you started.