"There's a couple of things..." is a very common colloquial slip, but it is not grammatically correct. The proper contracted form would be:

There're a couple of things you should keep in mind.

The non-contracted form you have exactly correct:

There are a couple of things you should keep in mind.

When "couple" refers to two people, such as a man and wife, it can be singular, as in:

There is a couple down the street to whom I would like to introduce you.

But, this usage is not as acceptable in the U.K. as it is in the U.S. The British will almost always say in such cases "There are a couple down the street...".

By: donald remero [ Moderator ]