We all forerun (hopefully), but we don't always forerun effectively. There's a couple of key ideas that we can focus on when we're testing our routes, so that we can achieve best results. If you haven't read the other articles on personas or the purpose of route setting, it would be easier to do that before reading this.
Adopt A Persona
When you're forerunning a V1, you need to become a V1 climber. Adopt the persona of the climber for whom your setting. If you fail to do this, you will often end up with routes that feel easy to an advanced climber, but demand technical or physical skills that are beyond climbers of that grade. This is easy to say, but incredibly hard to do. Especially as the discrepancy the route being forerun and your technical limit increases, but it's a skill you can train.
Instead of just 'climbing badly', try to have in your head the technical capacities of climbers in that grade range. Can they flag? Do they intuitively match hands or swap feet? Can they cut loose? Heel hook? The more you know about climbers of each range, the better forerunner you can be. This is when having a colour coded grading system is a huge benefit - you can build these technical requirements into your colours, instead of trying to work out the nuances between V0, 1, 2 etc. Don't stress about all V1 climbers, or whatever grade your working with, just focus on the climbers for whom your setting - be that in your gym, a competition, or whatever.
Communication: Focus On The Purpose
After forerunning, if changes need to be made, it's easy for things to drag on. What's wrong with the route, exactly? Is that move too strong? Is it just a preference difference between the setters?
Communication can sometimes break down entirely - especially when the setter has become attached to their creation. The answer is to simply focus on the purpose of the route. What is this route supposed to achieve? Identify the purpose, and then discuss how the route can be changed so that it meets it's purpose more effectively. An example:
Maybe it's a route that is supposed to be a sustained, endurance training climb with real flow. After forerunning, the setters identify a distinct crux move, that involves a powerful rock on, that leads into a no hands rest. It's a super cool move that the setter is very happy with. But, the purpose of the route is training - hard cruxes and no hands rests aren't appropriate - they're contrary to the purpose. The setter's consider the what the route is supposed to be designed for, and change the movement accordingly.
It's all in the communication. Instead of saying, "I don't like X about this.", a setter can say, "I think Y would fit the purpose of the route better." It might sound like a small thing, but it moves the criticism away from the person, and toward a shared goal - designing routes to meet a need.