Van Gaal arrived at the club after guiding the Netherlands to third place at the World Cup in Brazil last month.
The Dutchman has forged a reputation as an outspoken character over a long, trophy-laden career, and his attention to detail in United's pre-season training sessions have left a lasting impression on Evans.
"I think it is a lot more detailed at the training ground [now]," he said.
"They have spent thousands on it and a few of the lads have seen HD cameras around the pitch.
"We have this system at the minute where he can watch us on the pitch. I think a lot of teams use it but we are looking into it in quite a lot of detail.
"He is saying 'you should be five yards to the right'; we are able to see things that are happening live on the pitch.
"That kind of scrutiny is new to every single player. The case before was that as long as we got the results everything was fine.
"David Moyes would have looked at videos a lot so we got a bit of that from last year. [Now] we are looking at things in detail."
Van Gaal is well known for being quick to voice his displeasure when something is not right, and Evans insists that can only help the players as they look to improve on a torrid 2013-14 campaign.
"The manager told us it was going to be difficult because he is demanding and he knows that himself," he said.
"That is the standard he has set for us. It is everything from the clothes you wear to the time you have a meal and everyone eating together.
"He is quick to congratulate you when you have done well and is also quick to tell you when you have done something wrong."