As they say English is a funny language and we could not agree any less when we come to confusions such as these. You must be wondering what difference a c and s can make? Well, if you are a grammar fanatic, the wrong usage here might kill you, as one advice is a noun and other advise is a verb.
See the following examples:
1) I do not take advise.
2) I adviced her.
3) Sometimes we all need advice.
4) Please do not advise me.
In the first case, it should be advice.
In the second case it should be advised.
Third and fourth sentences are correct.
To clear the confusion, you need to know the theoretical difference between Noun and Verb, as in this case one word is former and other the latter.
Noun: It is that part of speech, which refers to person, place, and thing and in this case an act in itself (advice: suggestion for benefit). So, going by the definition, advice is the act.
Verb: it is that part of speech, which indicates action. So, going by the definition, advise here is the action by which an act (advice is given) takes place. You can classify the verbs into transitive and intransitive.
Hoping the difference is clearer and moving further, you can practice few examples below;
1) You will need my __________to win this award.
2) It is my call if I want to take your _______________.
3) My ________will make you a perfect dancer.
4) You really need to work on that good ___________.
5) Please ___________ me.
6) She ___________ him to rest.
7) I _________ you to rest.
8 ) Please __________ him to succeed.
Answers:
1) Advice
2) Advice
3) Advice
4) Advice
5) Advise
6) Advised
7) Advise
8 ) Advise