there are things that if you do

[navi tasan]

Which are correct:

1-There are things that if you do properly, people will will like you.
2-There are things that if you do them properly, people will will like you.

3-There are things that if you do properly, they will improve your image in the eyes of others.
4-There are things that if you do them properly, they will improve your image in the eyes of others.

[kfredson]

Which are correct:

1-There are things that if you do properly, people will will like you.
2-There are things that if you do them properly, people will will like you.

3-There are things that if you do properly, they will improve your image in the eyes of others.
4-There are things that if you do them properly, they will improve your image in the eyes of others.

You might hear the second and fourth versions, but not the first and third.

Having said that, I would say that all the sentences are grammatically incorrect. While you might get away with them in speaking, I would certainly consider them incorrect in writing.

Here is why: the word "that" requires a verb. You are doing things here. Thus the "that" must bring a result of some kind, and that must be expressed with a verb.

I would rewrite the second and fourth sentences as follows:

2-There are things that, if you do them properly, will cause people to like you.
4-There are things that, if you do them properly, they will improve your image in the eyes of others.