There are several tools out there to help make better decisions. Some of the these tools are quick and simple, while others appear a bit more complicated but really aren't.
Some of the tools that we use, to varying degrees, are a
Weighted Decision Matrix,
Decision Tree, and
QFD House of Quality Matrix.
The weighted decision matrix is the simplest and easiest to do, even in large groups. Another variation is to compare ideas directly against each other following the same template. For example: a group develops 3 ideas: A, B, and C with selection criterion of criteria 1, criteria 2, criteria 3, etc. To start you would define a control idea, we will choose Idea B. Then go through each of the criteria and compare Idea A to Idea B, and then Idea C to Idea B. Tally up the columns, this will tell you what ideas are better/worse than Idea B. Repeat this process by selecting Idea A or C as a control. By doing this you will know if Idea A is better/worse than Idea C.
A decision tree is very helpful at a high level and determining how to play the game. It can be used at more specific levels, but we use this as a guide to walking through the initial strategy talks and how we will play the game. It takes a decent amount of organization, but is a great way to be exposed to a lot of scenarios.
A House of Quality is probably the most technical of all the decision tools we use. It is relatively simple to use, but looks very complicated and overwhelming at a first glance. This is something I was taught my freshman year in college and have really benefited from using the tool.
There are many free and readily available templates, how to's, and examples for each of these methods on the web. I am glad to help if you need it. Really learning the design process and these tools will start to make your brain develop a "better" problem solving process.