As the title suggests, I have no clue how to read the colored trade routes. I thought I had it down, but when I followed the route, the prices actually went down. So I went in reverse and bought different stuff, and whaddaya know, sell prices below what I bought it at again. how the hell do I use it to trade?
You do not go into the galaxy map first.
First you go to the commodities screen.
It is best to select goods that are in medium or high supply, because in general the profits are higher and the risk of suffering a loss becomes higher when you buy goods that are in low supply and you happen to sell them where they are in low demand.
Compare the buy value of these goods with the galactic average.
This will tell you what profit you might expect if you sell these goods where there is a demand.
In general profits per tonne are higher for goods that are more expensive, so you might want to take that into account.
If you for example decide progenitor cells might be profitable (after comparing the buying value with the galactic average) you then look at the group it belongs to, which is medicines.
Do not buy them yet, but first have a look at where there is a demand in the galaxy/trading map to decide if you want to go there.
So now you go to the galaxy map's trading section. Select the group called medicines and disable everything except for the progenitor cells.
You will then see where they want the progenitor cells. If the location is to your liking you buy the goods and go there.
If there is no demand or you do not find a location you would like to travel to you must select another commodity and repeat the process.
It is virtually impossible to suffer losses this way. Your profits may vary though. That is the exciting risk of trading.