Advice and advise are pretty similar which is why they often get mixed up. The main difference, besides the spelling, is their part of speech.
Advice is a NOUN that means to offer a suggestion or recommendation.
For example: My advice is that you write 500 words per day. Tom gave Joan a lot of writing advice.
Advise is a VERB that means to give advice or counsel.
For example: I will advise Tom to start writing his article soon. It also means notification. For example: Janice advised Tom that she was finished with her short story.
Tweetable: Misused Words: Advice VS Advise