Boosters and handbooks
Boosters and handbooks are two different systems for pushing your output up in Big Farm, and plenty of players mix them up. Handbooks are permanent upgrades that I buy once with gold and they work forever, while temporary bonuses and craftable boosters only run for a limited time. Here I go through how both groups work and what to watch out for, so that the handbook you paid for really does what it is supposed to.
Handbooks are the best long term way to spend gold on the specific buildings I use all the time, while temporary bonuses and boosters from the clothing factory are worth firing off deliberately before a harvest or during an event, not buying blindly.
Handbooks permanently raise the output of one specific building

Handbooks (permanent boosters) are permanent production upgrades that I buy with gold in the library next to the main farm or from the offers at the bottom of the screen. Unlike temporary bonuses they work all the time and can be bought more than once - every further level raises the yield again.
Every craftable good has its own handbook, so this is a system of hundreds of small upgrades rather than a handful of universal ones. They typically cover:
- raw materials from fields, orchards and gardens, such as poplar wood, bamboo sticks, pebbles from stony fields or white sand from dry fields
- feed produced in the mills for the individual animal types
- finished goods from the processing buildings, such as the wood and textile factory, the mineral and metal factory, the candy factory, the bakery, the dairy, The Mermaid Bay, the clothing factory or the dye factory
I buy them gradually and deliberately for the buildings I work hardest - the effect stacks with further levels, so it pays off most on production I run a lot.
With feed it comes down to whether I use quick feed or the normal kind

For animals that can be fed either normal feed or quick feed (quick rabbit feed, silage for cows or sheep, pig swill), the same product has two separate handbooks - one that only applies without quick feed and one that only applies with it.
With raw wool from sheep pens in particular, the normal handbook does nothing if I use sheep silage - at that point I need the second handbook, the one made for silage. The same principle applies to milk from cowsheds, pigs from pigsties and angora wool from rabbit hutches.
Before I pour gold into either of them, I check which feed I actually use on that farm. Otherwise I end up with a handbook that has no effect on my current production at all.
Temporary bonuses speed up building and production and add experience
Temporary bonuses (temp bonuses) differ from handbooks in that they only run for a limited time and cannot be bought - they arrive as rewards or as part of in-game events.
They cut the time needed for production and for building and upgrading, and while some apply only to construction, including buildings in the cooperative village, others cover production as well. The important part is that the effect only applies to processes started while the bonus was active - anything I start after it expires gets no speed up.
Alongside the speed ups there is an experience bonus, which doubles (and in the stronger version multiplies even further) the points earned for production, building and upgrading, and a reputation bonus, which doubles the reputation points from completed missions. One version of the experience bonus goes as a reward to the cooperative that wins the global Champions League.
Boosters from the clothing factory target one specific building

Alongside handbooks there are also craftable boosters from the clothing factory, which raise the production output of one specific building for a limited time - a chicken coop, duck coop, cowshed, bakery, garden, field, cherry orchard or The Mermaid Bay restaurant, for example.
Each of them comes in a normal and a premium version, with the premium one raising output far more sharply. I use them deliberately before a bigger harvest or during an event, when I need to squeeze the most out of one particular building in a short time, not as a permanent solution - that is what handbooks are for.
One-off boosters outside the main system

There are also a few one-off boosters outside the categories above. The bakery bonus adds an extra piece of goods to the next batch you collect, but it only applies to goods I do not pay for with village dollars.
The temporary farm has its own pair of boosters that add workers or satisfaction - they only count on the current temporary farm and do nothing on the main farm. And when you are working through challenges, there is a booster that increases the number of challenge points earned for products made in the processing buildings.
Buildings and products mentioned in the text
FieldMain farm · 8 × 6
Clothing factoryGourmet farm · from level 19 · 7 × 6
BakeryGourmet farm · from level 30 · 10 × 7
The Mermaid BayFlower farm · from level 12 · 15 × 12
CowshedMain farm · from level 13 · 8 × 5
GardenGourmet farm · from level 19 · 9 × 7
Cherry orchardMain farm · from level 15 · 7 × 7
Candy factoryCandy farm · 8 × 6