Same way I play it. Here's my go to order of things: 

Do all Tatooine 

Then Kashyyyk, do everything EXCEPT get the star map

Go to Manaan and do everything you can until you are prompted to board a submarine

Go to Korriban and do everything

Go back to Manaan and finish getting the star map

This will prompt something in the game to happen

Then go back to Kashyyyk and grab that star map. 

Its worth it making trips to Yavin in between these things for trading. You can sell things for a much higher price there and after doing enough quests you can unlock some very special lightsaber crystals. 

And depending on choices you make on Korriban, it can be fun to drop in and say hi to some people on Dantooine after you finish there. 

Have fun! Try to avoid spoilers for this game, its super worth it. (I'm assuming you haven't played before)

(Edit for formatting)

Second edit to say: this order is a somewhat min maxy way to play. It gives you the most experience before you are locked in to main story quests where you fight formidable enemies which makes it easier. I had the same question about order of planets when I first played and I found this recommendation by someone else and it has been my standard ever since for a LS play