Sol tee nutz is certainly correct in that your first priority is making sure the person on the other side of the door is not a cop. That I'd 99.9999999 percent of the battle, and is won by reading reviews.
Beyond that, here are a few things those of us who have been violating the law in the U.S. for a very long time have learned:
1. Pay a little more. The more upscale the hotel, the less likely that any provider there is under surveillance. Hotels in big city centers are not law enforcement targets, whereas motels in poor areas of big cities and in small towns are. Canada as it progresses in law enforcement activity in this area may not follow this US trend, but I suspect that it will. Poor people are charged with crimes a lot more than rich people, so try not to look poor while you are committing a crime.
2. Look like you belong there. One incall provider told me that she liked the way I always carried a bag into the room. If was actually because I like bringing some sex toys and condoms, but she felt it was a tip-off to anyone watching if a lot of guys come to her room after walking through the lobby with no bags. Another advantage of bringing a bag is that incall providers love it when you bring your own towel. The biggest problem they face is getting enough towels from the hotel without being obvious, and the traveling US upscale providers hate lugging around a full suitcase full of towels.
3. Further to number 2, don't look like a dumbass. Every incall agency and incall independent's worst nightmare is having guy after guy sign in the lobby with a cell phone and carefully repeat "Room 302" while writing it down on the newspaper he has been pretending to read for five minutes while waiting for his cell phone to ring. This is a little less of a problem with texting, but there is no reason to sit and waif right in front of the check-in desk. Most hotels and motels have chairs that are not visible from the check-in desk.
4. Perhaps most importantly, obey the fucking traffic laws when leaving a motel. Most people turn to jelly if confronted by the cops. When an incall place is under surveillance in the U.S., the standard procedure is to stop a suspected john for a traffic violation after seeing him leave a motel parking lot, and then try to get him to admit to illegal activity such as prostitution or drugs. He does not have to admit to those things, but had often panics and does so. Not violating traffic laws minimizes the chance of him getting stopped since the cops do not want to look bad by making an invalid traffic accusation. One of the big disadvantages of small town motels is that a John likely parks right in the motel parking lot that is under surveillance and the cops see who enters and leaves. That is less likely in a big city hotel.