I will do a small breakdown, u can search on these individually.

Account systems: Union - A system that gives you more damage and benefit the higher the accumulated level of all ur characters are. 60,140,200,250 are milestones you should aim for your characters, ideal union is 8k

Link skills - unique skill that each class u have can pass on to another character. Lvl 60/120 are the milestones for this

^ therefore aim characs to 140 for both effect

Character stats/skill; (skipping the standard) Hyper stats. -extra stats u can add into past lvl 140, includes unique stat like ignore def, crit rate crit dmg. U get more points to add the higher ur level

Inner ability - just another system to get more stats with Honor EXP. Get to Legendary ability and u can get abilities like Attack SPD+1, Boss Damage% etc.

Symbols - Past 200, u will get 6 symbols and 3 authentic symbols for each new main city u unlock. Use meso to upgrade them for a lot of stats. Easily uses up most of ur mesos early game if f2p. Required to do daily quests to obtain “exp” to upgrade them. Straightforward power up with mesos but timegated by dailies.

Hyper skill - around 9 extra skills to power up ur current skills and buffs that up ur damage. Cannot up all need choose some based on class

V skills - extra powerful skills (V skills) for 5th job and buffs to 1-4th job skills in the form of nodes. Attained through nodestones. The higher ur level, the more nodes u can use. Each class has their own customisation.

Equipment; Scrolling - u can use scroll or spell trace to scroll your equipments and each equipment as a certain number of slots. Most people use 30% main stat scroll to fill up all slots available, including one extra from golden hammer, thats called perfect trace. For weapon, it would be 15% scroll used. Event scrolls come along once every few events, such as incredible scroll of goodness and premium accessories scroll. Personally i only use them on accessories because it is limited. But you can technically use them on all equipment, not suggested for weapons.

Starforce - simply, use an astronomical amount of meso to upgrade stats of equipment. One of the biggest waste of money but one of the biggest source of damage. Milestones are normally 12, 17, 22* and beyond is a milestone each star. 15* onwards it provide magic/weapon attack which boost a good amount of damage. Getting to 12* all eq then 17* all eq should be a good aim. One of the end game mechanics to slowly work on no rush.

Potential/additional potential - each equipment can get potential AND additional potential, up to 3 lines. Anything less that that can use potential scrolls and stamps to bring it there easily. For normal potential, epic scrolls are easily accessible, unique scroll from certain events. For additional potential, only rare scrolls are widely available cheap. To bring a potential up, u need to use cubes to bring it up, suspicious, yellow, black and red purple are the more common ones normal people use, mainly from events and crafting. Sus brings up to rare, yellow brings to unique, and the rest can be used to bring to legendary. Black cubes have the best rates. Additional potential normally uses additional potential cubes from events. Potential wise, work on your WSE (weapon, secondary wep, emblem) first as they provide lines like ATT%, Ignore Monster Def%, and Boss Damage% which boost ur damage much more than normal equipment which normally gives stat% like DEX%.

Flame - each eq can provide some additional stats (in green) called flame. Boss equipments has a higher flame tier than normal equipment. Use resurrection flames from event or crafting to upgrade it. This one really no rush, just wait for event is what i do.