I may use the word "that" too much in my writing. I need some advice.

For example:

List all items you wish to purchase...or
List all items that you wish to purchase.

To ensure you receive credit, please include the following...or
To ensure that you receive credit, please include the following...

I would use the second sentence in both instances because it seems to flow easier.
Not really anything to laugh about, haogide.

It is sometimes not an easy choice, guest. If the meaning is clear without it, feel free to omit the 'that":

'List all items you wish to purchase.'-- here there is no problem of interpretation, so 'that' can be safely omitted.

'I found you have been omitting your apostrophes' -- We read and listen linearly, so the first three words, 'I found you', may temporarily mislead us; in this case, a 'that' might make the meaning immediately clearer: 'I found that you have been omitting your apostrophes.'

It is usually a matter of style, not correctness, and there will be different opinions as to the clarity in each case. As you say, it is often a sense of 'flow' and no more that will influence the choice.

Invest in Bitcoin on the World's Leading Social Trading Network

Join millions who have already discovered smarter strategies for investing in Bitcoin. Learn from experienced eToro traders or copy their positions automatically!

I would use the first sentence in both cases because it seems to flow better! haha, I guess we just have 2 different opinions there!
Try out our live chat room.
 Mister Micawber's reply was promoted to an answer.
To Mister Macawber...thank you for your response and advice. I appreciate your time.