Reputation with the Tillers is gained by doing sets of dailies, each rewarding reputation with the Tillers except the cooking quest, which rewards Ironpaw tokens.
Besides gaining reputation with the Tillers you can also gain friendship with individual members of the Tillers. At certain intervals in your rep farming they will offer quests that award reputation with them, but there is also an option to do it faster. Scour the Heartland for Dark Soil patches and loot them. You will find objects you can turn in with them to gain friendship, not restricted by daily limits.
These patches are all over the Heartland and can best be seen from high altitude if your graphics card can handle that. High altitude removes shrubbery etc making the patches very visible.
Don't just turn in items with any NPC, every item has two NPC's that award more rep than if you turned it in with someone else. Below is th etable for turnins.
Ella: favorite gift is Jade Cat.
Fish Fellreed: favorite gift is Jade Cat.
Farmer Fung: favorite gift is Marsh Lily.
Gina Mudclaw: favorite gift is Marsh Lily.
Chee Chee: favorite gift is Blue Feather.
Old Hillpaw: favorite gift is Blue Feather.
Sho: favorite gift is Lovely Apple.
Jogu the Drunk: favorite gift is Lovely Apple.
Tina Mudclaw: favorite gift is Ruby Shard.
Haohan Mudclaw: favorite gift is Ruby Shard