You need to have a great feel for design and what will create a big buzz.
Feeling for what is hot and cool and might create a buzz.
Take inspiration from Guerilla marketing.
I also added our logo dont make it so that it takes all attention away from important target which is the "buzz-design" .
Make people want to know more about what is on the shirt and the "buzz-design".
So, in conclusion, what is important is that the shirts attract attention and that the design creates a buzz and will interest people in further finding out about MrGizmo and what it does.
Also tke colors from www. mrgizmo. se
I have added a rar file whit all fonts, Ai logo and patterns (you my use but it not about is more for a feeling)