Advice is usually an uncountable noun in standard English. That means it does not normally use a or an ordinary plural form. Even though advice can be broken into separate tips, English treats the word as a general mass of guidance, similar to words like information or furniture.
Because of that, these forms sound most natural:
- some advice: “Can you give me some advice about my resume?”
- a piece of advice: “Here is a piece of advice, arrive early.”
- lots of advice: “She received lots of advice from her mentor.”
And these are typically avoided in standard English:
- “an advice”
- “advices” (as a plural noun)
If you want to count separate items, use a counting phrase: two pieces of advice, three tips, or several suggestions. For contrast, compare: “He gave me some advice” (uncountable) versus “He gave me two suggestions” (countable). In formal writing, sticking to these patterns helps your English sound more natural and precise.