be carefulA colloquial way to tell someone to be more careful; หน่อย softens the request, but the phrase can sound sharp depending on tone and context. Often followed by สิ for emphasis.
be a little carefulA colloquial way to warn or ask someone to be more careful. หน่อย softens the command, but the phrase can still sound reproachful depending on tone.
TH: จับแก้วให้ดี ระวังหน่อย เดี๋ยวทำตก
EN: Be a little careful with the glass, or you'll drop it.