OK, now we are going to weather your suit and helmet. I like to use a airbrush for this. You don't need a real expensive airbrush, I use a Paasche 2000H H single action airbrush.
You can get them on ebay for around $50.00 but you will need a air compressor to run it. I use water based acrylic paint and I used Grimy Black on this suit and helmet. The water base paints are nice because of the easy cleanup.
I always try to highlight all the great curves and shapes on the suit as well as add some depth and realism to it. I start by taping off all the areas that I really want to stand out.
The other areas I use a loosely cut template like you see below. Hold the template and spray.
Once finished with the first coat, remove the painters tape and lightly spray the areas that were just covered. You don’t want these areas to be bright white. Just a lighter mist than the first one.
On the helmet do the same. Try to spray the offset and recessed areas to give it a little depth (Sorry, I didn't get a photo of this).
Once finished with the airbrush I knock the suit down with some sanding pads. I use the Gator Grit Flexible Sanding pads. I use to be able to find these at Home Depot but they no longer carry them. I think they can be found at TrueValue.
Another option is the 3M Sandblaster Pads. They can be found at OSH.
Do NOT use sandpaper or the 3M sanding blocks. They are just too rough on the painted suit.
The photo below has the strap on the left sanded down and finished.