거기서 거기 is very useful expression :) I think in english it sounds like more or less same, so it could also meam that there is nothing special or difference.
거기서 거기 is used to indicate that you do not need to consider about it carefully.
For example, 스마트폰 다 거기서거기야 which means all smart phones are more or less same.
An example of myself, i usually say 거기서 거기야 when i do not wanna wait my friend considering what to buy for his or her clothes. 다 거기서 거기니까 아무거나 사. This means that all of them looks same, so just buy any clothes.
Another kind of expression i would say is 동네방네 which means all over the town.
I copied the sentence from another website to help you understand :
동네방네 소문내다 The rumor spread through all over the town.
This is also very good expression to use :)
Learning korean should be quite challenging. I really admire you studying Korean.
I hope you enjoy studying it :D