I understand something is translated as "quelque chose", and a few things as "quelques choses". Is one or the other more commonly used in speech, to prevent the ambiguity here? What are other ways for me to say each of the two?
Context is usually enough to distinguish them.
In the first place, if either is the subject of a sentence, the verb will be conjugated audibly differently in almost every tense.
Quelque chose est arrivé.
Quelques choses sont arrivées.
Of course, we can be confused if it's not the subject of a sentence:
Il se passe quelque(s) chose(s).
The unusual word "something"
Even then, I wouldn't say there's as much overlap as it might seem. "Something" is quite a different animal from "a few things".
"Something" isn't really the singular of "a few things", even if in French it grammatically looks like it. Instead, "something" and "quelque chose" just fill a gap where you don't know what you want. They're more like variables than nouns. (Notice even the lack of agreement in the first example sentence above — thanks, Stéphane.) For that reason, the sorts of conversational contexts where they show up are liable to be pretty different and you'll probably know which one the person means.
Even the stress changes a little; the English stress patterns here roughly match the French:
Je cherche quelque chose. I'm looking for something.
Je cherche quelques choses. I'm looking for a few things.
Je cherche quelque argent. I'm looking for some money.
The first sentence is stressed on cherche / look. The other two are stressed on the last word. Even if you deliberately emphasize quelque chose / something, the stress falls on quelque / some. In other words, quelques choses behaves more like a normal noun.
For the same reason, it'll be easier to switch out the parts of quelques choses than the parts of the more fixed quelque chose.
choses can be replaced by trucs, for example, or articles depending on the context.
quelques can be replaced (albeit with changes in the meaning) by plusieurs, bien de, plus qu'un(e), certain(e)s.
If you try to replace the parts of quelque chose like that, the meaning stops being "something" and starts being "a thing", "one thing", etc., which is different.
I'm looking for a thing. (?)