Adventure Skills
There are several skills that you unlock as you increase your Adventure Rank just by playing the game and filling up your adventure handbook. These skills range from raising inventory space to useful active skills and even a book that allows you to respec infinitely.
To learn these skills speak to Roland in the northern part of Prontera city. He offers a shop that lets you spend adventure skill points on these skills. You get an adventure skill point anytime you raise your adventure level.
As I mentioned all you really need to do is explore the world to raise you Adventure Rank. This means killing at least one of each mob, taking pictures, meeting new NPC's, etc. Every 5-10 adventure levels you’ll receive a quest to raise your adventure rank to the next grade. These rank ups are what give you access to new skills and provide stat bonuses to all primary stats like STR and DEX.
A total of +9 to all base stats is obtained at the maximum adventure rank B!
Example of the skill "Prepare for Elite" which combines up to 7 buffs into a single skill which incurs one short case time and cooldown
Ymir's Notebook
At adventure rank C you should be able to purchase the skill "Dimensional Fracture" which will give you the item Ymir's Notebook. This book allows you to save and load builds from town, guild, or your home. Each character will have this put into their inventory once you obtain this.
Using the book brings up this interface which shows you character names and build you've saved. You can double tap on one of your saved builds to rename them if you need. Stat allocations, skills, Aesir, equipment, and Runebox allocations are all saved to this book to be loaded up quickly as needed.
Although this is great for multijob you can actually use this to get free skill resets. It saves all allocations so if you reset everything and save without placing any points, it will load this up anytime you wish to be reallocated however you wish. This allows you to toy with builds or try builds that you may want to switch to but need to determine if you're strong enough to make this change.
Please note, builds are saved per character but save slots are shared for your account. You start with two free slots and a third which becomes available if any characters on your account have an active Premium. Another slot may be purchased for zenny but after this you must pay BCC per extra slot.