Lots of great info on here. When I first started coming out, I cruised the university bathrooms a lot. After I figured out the routine, I had lots of great success.
1) Be patient. It often takes time before somebody looking comes along, but if you are patient, you usually can find something good. Cruising the busy toilets/areas is a waste of time to me. It is too busy for anything to happen. People always coming and going. The bathrooms/areas I had the best experience were the lesser used spots.
2) Always be aware of your surroundings. In the bathrooms, always be aware of the sound the door opening makes. Most of the action I saw took place in the stalls. I always paid attention to when the bathroom door opened and how many men came in and/or left. I also would check out the stalls to figure out which ones (if any) had glory holes. Also look for really small holes in the walls. You can watch guys and figure out if they are looking or not. One of the university bathrooms was in a very old building and the bathroom was laid out weird. The stalls didn't have doors on them and there were 4 urinals located on 3 different walls in a small area. I tried out all the stalls to figure out the best cruising spot. There was one stall that I could watch 3 of the urinals and the main sink area. That was the cruisiest location by far. I got lots of action from that stall. There was a local park that used to have lots of action. I knew all the trails in the park and where they started and ended. Some of the trails got close to each other in spots and you could spy on people out in the woods. Other spots were super secluded. If you do play, be aware of people coming from either direction.
3) Don't be stupid! I always waited to do anything until I was sure the other guy was interested. I might grab my crotch, give it a rub or two. But I never took my dick out until the other guy had taken his out. I know the police were cracking down on one bathroom at the university union. They put a video camera pointed at the door of the bathroom. I know a few guys got busted for messing around in that bathroom. I think the university cracked down on that bathroom because it was near the arcade games, bowling alley and food vendors. That area was popular with high school students and families with small kids. The other bathrooms in the same building, they never cracked down on activities in those bathrooms. So be smart about where you play. Check Squirt.org and look for locations. Read the comments and see how safe it is there.
4) When I cruised from the bathroom stalls, I would look for other guys that were in the other stalls longer than usual. Listen to hear what they are doing. If they are using the bathroom, most likely they aren't cruising. If they are just sitting there, chances are they are looking. Some bathrooms have lots of shiny surfaces. Look for their reflection to see if they are jacking off. Or see if they are busy looking under the stalls too. If you think somebody is looking, move your foot close to their stall. Tap your foot. See if they tap back. If nothing, they might not be looking. If they do tap, move your foot closer and tap again. See if you get a response. I used to take a pen into the bathroom me. If I thought they were interested, I would write a note on the toilet paper and slip it under the stall or through the glory hole. Most of the time, I would ask if they were interested. If they weren't interested, 99% of the time, they would either not take the note or they would flush it and leave. If the bathroom was busy, I would suggest going to another restroom that was usually not busy.