Cheap tweaks...What would YOU reccomend?

Is there any danger with DIY items? I have been trying to get my room acoustically treated and I have been researching the possibility of making my own stuff. I have a friend of mine that has built acoustic panels and bass traps using fiberglass and they work fairly well; however, I wonder how safe it is to have things made out of fiberglass in a room where people sit and relax and breathe the air in. How safe is it? Does anyone know?

I just tried some SOLID ROSEWOOD ISOLATION CONES I bought and they are extremely good! Bought my Mid-range back to live! 25-30% improvement with vocal & string and 10-15% improvement to soundstage and accuracy. They are not cheap, but once you tried them, you will be stuck! I bough 10 sets!

Infinity, how do you measure these 25-30? changes, especially the improvement to accuracy?

Well it's just a sense of percentage, totally personal... Its a adjective of how much and it does not decrib in EXACT

So many great tips. Ebarker2 advice is next to nothing in cost but great advice. Dedicated lines are not practical for many but if possible one of the greatest tweaks. Good quality
Outlets, keeping all connections clean, keep PCs and wires off one another. Keep components a reasonable distants from one another. Clean all fuses. Not fooling, in some cases this really works. If you do not have dedicated lines, Subaruguru's idea of turning off the fridge will surprise you. You may try putting small pillows in the corners of your ceiling. Drapes look good and in some cases can be a very effective tweak. Not a cheap tweak, but good racks/isolation devices are IMO as important as your audio gear. And as many have said and can't be said enough is speaker placement.