Note: The focus of this page is to inform you on what the best skills are to obtain first as you progress through the story. Although you are able to obtain every skill in the game.
To make this a little easier we're going to break them down into the their own individual section, so Force, Survival, and Lightsaber.
As you progress through the game you'll eventually unlock Force Push, this will open more options in your Force Tree. Your main focus at first is to unlock Force Attunement as a lot of the skills/combos in the game require a lot of Force to use, then get Mass Push to stagger serveral enemies. Once you gain a few more skill points you'll want to unlock both Enhanced Force Recovery which will allow Cal to regain Force upon defeating or blocking an enemy's attack and Howling Push. This ability is arguebly broken as you can launch a group of enemies on the floor or even off the side, this is also the case with bosses.
Next up you'll want to grab Grasping Pull which is also another overpowered skill as it will allow you to pull enemies towards you and one shot them, now you'll want to obtain Greater Force Attunement and Ultimate Force Attunement when they become available, as these both will increase Cal's Force allowing him to perform more Force Pushes or combos. The last two main skills you'll want to obtain from this tree is The Power of Friendship which will allow BD-1's Stim Canister to restore your Force back to full and Howling Pull to enable Cal to pull groups of enemies around him.
The first skill in the Survial Tree that you'll want to pickup is the Surival Skills as this increase Cals maximum health, now you'll want to work your way up to the Agile Deflection skill as this will allow Cal to deflect any incoming bullets when you're trying to sprint through areas or taking on multiple enemies. Once you've saved up a few more points, you'll want to pick up Improved Stims, this will increase the amount of health BD-1's Stims will give you.
Finally, obtain the Personalized Stims skill to gain even more health from Stims and then pickup Enhanced Survival Skills and Expert Survival Skills to increase Cal's Health.
You'll want to pickup Dash Strike first as this will allow you to close the distance between you and bosses, and then grab Improved Dash to allow you to close even larger gaps. Now work your way up to get Whirlwind Throw, as this works well with Howling Pull because you can pull groups of enemies close to you and then throw your Lightsaber around your body which will take out all the enemies.
Collect a few more skill points and grab Sprint Strike, this skill will allow you to perform a powerful first hit, then obtain Lightsaber Mastery which will increase the amount of damage your Lightsaber can be deal.
With the remaining skills left you can just go for what takes your fancy.