Game Progression

Once you hit base level 80 you'll get a popup indicating a new bar has been added to your Auto Skill list.  If you open your skills list you'll notice there is now a little cat icon in the bottom right corner.  Tapping this swaps to a second set of auto skills.  This means you can now have one set for farming and another for when you're doing group content.  You probably don't need to alter this now but several classes can make great use of this at higher levels.

At base level 80 a new raid instance is unlocked via the instances menu called Thanatos Tower.

This is a weekly instance where two parties (up to 12 people) clear four floors, each rewarding you with several runes for your rune box, zeny, and other nifty rewards.

You'll want to find people to help carry you through this because it's not something a new player can tackle on their own.  The third floor actually requires four people to spawn the boss so you'll need at least three other people to get through this every week.

For details on this instance, strategies, and more, read up on Thanatos Tower.

A new instance is also available at base level 80, the Seal under Sakura time rift challenge.

The novice version rewards you with the same loot as the level 60 rift challenge Morroc Shadow.

Note that the Adventure and Warrior modes can drop advanced Garment and Footwear which did not drop from the higher difficulties of Morroc Shadow.  As these have better stats and can roll augments such as % damage you should try to run this on at least Adventure difficulty to get these upgrades.

For a refresher on these dungeons read up on Rift Challenges.

By this point you're probably looking at the bottom of the Targets for Combat Time below thinking you're falling behind.  Chances are you still cannot one-shot orcs or any other mobs in the 70 range, possibly even unable to do this for level 60 monsters.  This is perfectly fine!  These are just suggestions, not the gold standard for players around this level.

Leveling will slow down significantly for new players since your stats are just not high enough to contend with these creatures.  It's going to take some good gear upgrades and most importantly lots of adventure handbook stats to boost your atk/matk high enough to start one shotting again.  Do not forget about cards in your weapon too!  This is a significant portion of your damage and at this point it is mandatory, you will not one shot anytime soon without these things trust me.  If you haven't added your second weapon slot I highly recommend making this a priority as this will add another 10-15% damage.

When things are slow don't get impatient!  Focus on farming whatever you can kill in one hit that gives you the most zeny.  Try to find mobs that drop rough Oridecon or Elunium as you'll need it and can sell it off if you need some extra money in a pinch.