Herblore

[Raptor]

Any tips how to max it? It takes sooo long :-(

[Kagora]

1: try to maximize your preservation chance
2: if you run out of herbs you can thieve the Merchant in the Farmer's Market for more herbs while also waiting on them through farming
3: try to avoid the potions that will consume more herbs for less overall XP (leathal toxins pot vs elemental/herblore pot vs generous harvest)
4: get the +XP items and bonuses first/make sure they are equipped (agility, astrology, fire making skillcape, ancient ring of skills)

[Reynolds]

Or just farm offline. Set it up, go to work, come home and celebrate your new potions.

[Lowlight]

Doing this now. It is incredibly boring, and that's saying something for a game that is basically played offline.

[SillieBillie~]

Get the township skill outfit as quickly as possible, all four pieces can really help, bonus if you can get the coin and combine all the pieces.
Get the non-combat XP gain ring from fishing as well.
Astrology stars Qimican and Rosaniya at 99 will give you more perks that will boost it.

Other than that just farming to get herbs. Make sure you've got everything for farming too.