I keep spools of the basic colors on a thread stand
behind my machine, along with several spools of colors I use frequently. Extra spools are categorized by color (Light to Dark shades) of each basic color, place them in rows, so I can see the color of each spool, lying on its side within large gallon size ziplock freezer bags. I can seal these bags and store them flatly in drawers, or other containers. Air and bright sunlight will dry and deteriorate threads when exposed for a lengthy time, causing thread breaks while stitching. I can see at a glance the colors, should I need one I do not already have displayed.
Angel

I've got a couple hundred colors which is nothing compared to some cuties but my DH bought those thread stands at Joanns, mounted them on the wall behind my machine and poof they are all at hand. (and all full - giggle)

My threads are kept in large plastic boxes and sorted by colours. I also have a lage box full of large spools of 5,000m threads but as I dont have many of these they are all together. Since I started keeping them this way the collection has grown and I need to get some more boxes and resort, but sewing is more fun and I have not bought more storage space - yet

I keep mine like this:

Racks and storage boxes... wonderful inventions. But, when I'm working on a design, I tend to set the spools on my work table next to my machine. I guess I do this so I can see what I've already used when I'm looking at my color schemes. I gave up keeping my colors coordinated a long time ago. LOL!

I keep the plastic boxes from fresh strawberries, and after I clean them and dry them, I sort my threads into them. They are see through so easy to see the shades of thread from all sides, and they stack easily. I have an old end table that I use beside my sewing machine cabinet. It allows me space for storing the boxes in site, and also since it has 2 shelves, I keep cans on the top shelf with zippers, scissors, and other sewing needs in them. It also gives me a place to set my embroidery machine attachments where I can reach them easily.

I found these plastic drawers at Walmart, they run about $8.50 in the usa and $14.00 in canada, I have 4 sets and they work well for me, I sort the colours in groups of blue, green, yellow/orange etc. I like things simple, you can get wooden drawers at metroemb, but they are pricy.

My picture didn't load for so reason or another, I forgot to mention to I like to keep my threads in a box or drawer because we live in a very dry dusty area so the threads stay dust and lint free, I can dust the house twice a week and still have dust everywhere, so depending on where you live, you can decide on drawers or wall units like Bowlds ( The wall unit is very stunning though )

As a newbie I dont have that many threads but I am starting to build a collection up. At the moment I put my threads and bobbins in a big plastic egg box.

Recently I bought a 10-drawer trolley - aluminium, I think, and plastic drawers. I've seen them with ten different coloured drawers but this one has two each of blue, yellow, red, green and purple and I sort the threads into light and dark shades of each colour.
The trolley has small wheels and I have it near me when I'm stitching designs and then wheel it out of the way when I've finished. It's very convenient and light-weight.
It will hold dozens more spools of thread than I have.
AlmaG.