Im looking for some advice as to how i should handle a basic form in PHP.

1. when you post some input text is it best to user addslashes() or strip_tags(). What is most common?

2. What would the following code do? Would I need addslashes or anything of the sort if i am using mysqli_real_excape_string?
Code:
$name = mysqli_real_escape_string($dbc, trim($name));
3. Im having a serious issue with apostrophes.
It always adds a backslash infront of the aposrophe, and cuts off everything after the apostrophe. Even if i DONT have addslashes anywhere on $POST. Sometimes it even adds multiple backslashes. WHat is going on? How do I fix this without compromising any security?