Credit Score Management

I have recently went to the USA from another country. I have years of credit history where I came from, but here I have about 4 months – one credit card with a whopping $200 limit. My VantageScore is 635.
What is the fastest way to increase this score. Also, can I qualify for an auto loan with this score, or is it too low?

My credit score is around 500. I’m 21 years ancient and I have made some pretty poor decisions regarding my financial obligations. (PLEASE, do not post any negative information or comments telling me to get back on track and how vital excellent credit is. I KNOW THIS and since March of this year, I have gotten back on track.) How much can my score go up after I continue paying my bills on time and get some bills out of collections? Thanks.