If you (do something), (someone) will (do something)

Use this kind of sentence to talk about what the result of an action will be. Say this when you're sure or pretty sure what the result will be. It's usually used when you have experience with something. For example:

If you cook it for too long, it'll turn out tough.

If you press this button, the whole thing will turn off.

When you don't have experience with the results, it's common to use "probably" or a phrase like "I'm sure that ___":

If you search online, I'm sure that you'll find some nice houses in that price range.

If you ask Brian, I bet he'll give you a few good recommendations.

show (someone) respect

"Respect" is the feeling that a person is good, wise, intelligent, or cool. When you "respect" someone, you feel this way about them. But to "show respect" means to be polite to someone, and treat them like a valuable person. You can "show respect" to a person by not interrupting someone while they're talking, letting them make their own decisions, asking them polite questions about themselves, and so on.

return the favor

When someone does something nice for you, and you do something nice back to them, you call that "returning the favor":

You've helped me out so much, so I just wanted to return the favor.

But the phrase "return the favor" now has a wider meaning than just doing something nice in return to a person. Now it can have a more general meaning of "doing the same thing back to someone that they do you".

It's mostly used with positive actions, but it can also be used with some negative actions too in an ironic way. For example, if you're playing chess with someone and they take one of your pieces, you can say this when you take one of theirs:

Allow me to return the favor.