El vs La

Question

I see that “el” and “la” are based off masculine or feminine. How do I know if a general noun (e.g. car) is masculine or feminine tense?

Answer

For inanimate things, we can often get the gender from the ending of the noun that we are using. Most common: masculine ends in o, feminine ends in a.  Ex: el taco, la casa. Also common: masculine ends in r (el color), n (el avión), and s (el gas).  Feminine ends in d (la edad), ción (la nación), and sión (la misión).  These are the basics and there are more endings and exceptions to learn. But it is a good place to start.

Answer

Hola Liam 
As Marcos said, there is only a general guide to what is masculine or feminine, there are certain endings that tell you which gender they are (but there are exceptions). Lots of the nouns need memorising, like nouns ending in -e, which could be either gender ( el coche, el parque... but la gente, la calle...)
Here are two Kwiziq articles that talk about gender. If you scroll down when on them, you'll see all specific lessons we have that are related to each gender. I suggest you add them to your notebook to start mastering that topic. 
Masculine gender
Feminine gender
Un saludo