In The Minish Cap, the RNG seed is the same every time after a hard or soft reset and gets advanced whenever something in the game calls for it. The RNG value advances to the next value each time something in game wants to perform a random function, for example: Link's rolls, NPC movements, Enemy attacks, Item Drops.
Simple manipulations are easily performed as the RNG will always be exactly the same at the start of a manipulation, however longer manipulations become much harder as the player has to ensure RNG advances in a predictable way.
Below is a table of actions that can change the RNG seed.
Another important thing to note is that Link's health and item counts (bomb, rupees, arrows) will affect RNG manipulations that are used to obtain drops, such as the green kinstone manipulations. These HP/item counts will not impact manipulations unrelated to drops (Octo Manip, Darknuts/Vaati Manip, etc.). All item drop manips are designed assuming that Link has: More than 1 full heart, more than 10 rupees, more than 0 bombs, and more than 0 arrows. If any of those conditions is false (IE. 3/4 hearts or 0 bombs), item drop manipulations will not work.
It is to be noted that the way the game advances RNG differs between versions of the game (US/EU/JP). Since the majority of runners play on the Japanese version, the manips are designed for that version. If you wish to run on a different version, you may have to tweak existing manipulations.
If you are running glitchless, it's also important to note that any% Darknuts/Vaati Manip will not work exactly the same, a slight adjustment must be made to do the same manipulation in glitchless. Doing 4 less rng calls (rolls) by the time you reach the Big Door will bring the RNG into line for the rest of the manipulation.