When you get the item, send yourself an email with the location of it once you have put it somewhere.

Why are you buying stuff in advance? Buy what you need for a project when you are doing the project. It's not like food for an emergency. No one has storage anymore. But if you want storage, just go get some fun containers, masking tape and felt pens, or stick on labels.

Toolbox! Or, if you have really tiny parts, you might want to consider an embroidery floss organizer box - I use them to hold earrings. Small compartments, and a lid that snaps shut.

The biggest key to being organized (physically) is to find a specific place for certain items, and put things back in the same place every time. I’m an organized person so I don’t lose things very often. It’s just a habit that you make yourself do. Such as always putting your keys in the same spot, or always putting your apples in the same part of the fridge, etc. The most disorganized person I know never puts anything back in the same place he took it from, and as a result his place is a complete disaster and he’s frequently late because he can’t find his keys, his shoes, or whatever. He’s constantly mad about it but he’s made no attempts to change, so obviously he likes it that way. If you really want to improve, just set up the habit and follow it religiously until it’s second nature.

They have these cheap fishing tackle type boxes, transparent so that you can see your 4 rows by 5 columns of items all in compartments. Maybe $3-4. Works great and has a handle so you can move it around easily. I use it to organize small metal pieces.

Get one of those ikea grid-type shelving units, the fill it with chambered boxes, then fill those box's chambers with dividers or sub-boxes, and label everything in alphabetical order.
That, or maybe find some Ritalin.

You may have chronic disorganization disorder. Google it - there are helpful resources out there! :)

I left some out by the garbage after finishing a project, then found a use for one last night. Fortunately it was still there, and exactly the right width, so I only need to make one cut. Lucky me!