Ok. I came across this picture on the forum the other day and it made my blood run cold!

Attachment:
Danger.jpg
Now I realize that everybody prototypes in their own way. But this is EXTREMELY dangerous and certainly no way to handle high voltages. Looking at this picture, I wasn't quite sure where to start so I thought I'd start at the beginning.
This circuit appears to be connected directly to the mains without the benefit a a switch, fuse, nor any type of protection. So I thought I'd start there. Mains voltage is lethal.

It will kill you if you give it the chance. So don't. To that end, here is my first recommendation. Develop a simple interface to allow you access to mains voltage that provides some protection. Here is my simple solution.
Attachment:
PB 2.jpg
This simple box provides a sure connection to the main plug, integral grounding protection, a power switch, a live indicator light, surge protection, fused over current protection, and sure rigid connection for power transformer leads. And the best part is it cost me less than $10 USD and about 1-1/2 hours to put the whole thing together. And here is the simple schematic.
Attachment:
Schematic.jpg
If you are going to be working with straight mains voltage you need something like this.
Here are some other simple rules to follow when working with high voltages:
1) Every component should be rigidly attached to something (a screw terminal, Fahnestock clip, etc.)
2) Avoid alligator clip leads. These pull off and can represent high voltage snakes just waiting to bite.
3) Keep it neat! A tangled mess of high voltage wire is a SERIOUS accident just waiting to happen.
4) Think, Check, and Think, Check again before throwing the power switch.
5) Never work with high voltage when you are tired, distracted, upset, intoxicated, or in any way impaired.
Ok. I'll get off my soapbox now.
