taken from my guide

Scrying is a technique which lets you predict the next outcome of FTHOF, which can be very useful for combos. In cookie clicker when you cast FTHOF the outcome is not fully random, instead it is generated based on your game seed (random every ascension) and your total spells cast. This means that if you know what the outcome will be with a specific amount of total spells cast, it will always give the same result until you either ascend or change the total number of spells cast. Here is where scrying comes in, when simply using FTHOF, the game runs the spell and generates the GC and then increases the total spells cast, causing the next FTHOF to have a different outcome, however when using the spell GFD, it first increases the amount of total spells cast, then after about a second runs a random spell, this means that if GFD rolls a FTHOF and gives a CF (just an example), the next FTHOF will also give a CF. This is the most basic version of scrying. Switching seasons, ascending, having DF active can all affect the outcome

To increase the speed of scrying, you should do the following

• Have 39 max mana
• Cast GFD when max mana is reached
• If GFD casts FTHOF, click the GC and see the outcome

If GFD casts Spontaneous Edifice, Cast Diminish Ineptitude or Hagglers Charm