I am sure this has already been addressed somewhere, but i have not found it yet (i will keep trying). Is there a guide that shows where to farm for particular mats? For example: I know dielectric cell fiber and green goo can be easily farmed on Drommund Kaas. After that, I dont remember which planets give which resources. Trying to buy on the GTN is sometimes expensive and takes longer than farming myself.

Thanks

Here is an article with tables that show which planets has what mats, for all gathering skill :

http://swtorhub.com/crafting-materials-location-guide

torhead is pretty good

when i google the mats i want to farm there is usually a torhead entry near the top of the page

go to the "reply" tab and you'll see what people have said regarding the best ways and places to farm the mats

the only problem is much of the data can be outdated but, luckily, not too much has changed from early on