First you need to know what you are looking to obtain on an item.
For a list of possible options you can use https://wolcendb.erosson.org/
Example for ENDGAME gearing: I want a 2-handed material damage weapon.
1. What base item do I want?
The highest base item is T16 Profane Executor.
Starts Dropping around 60-80 mob level
2. What do I want for the Suffix/prefix?
I want to aim for 1 Flat Base material damage Suffix.
Highest Suffix starts appearing around mob level 140, 160 or higher is Ideal for farming removes lower Affix drop pool
This way I can Craft % Material damage using gems
Note: if the item can have 3 sockets you will need 3 sockets filled with gems on the item.
The suffix I want to see before crafting would be the Weapon life leech and decent Critical damage with a top roll Flat material damage.
This is a good investment of resources cause I know if i land the % material damage with my gems there is a very good chance this will be an upgrade or has the possibility to become a god tier item.
Some times it does not land but you can still have a chance to revert a bad roll with an Abyssal Tear.
IF you miss and remove wrong stat. Use an Eriban tear try to get correct stat back. Failing after using one CONSIDER THE ITEM BRICKED.
When you land the mods.
The suffix pool only has a few options left material ailment chance would be nice but not landing it won’t break the item.
LANDING another flat material is really what we are looking for either Toxic or rend both scale the same. (rend slightly favored with gates of fate options)
Going from Yellow to Red is done with the Dark Market.
This part is a PURE gamble using gems here will not help.
If you miss but it’s still an upgrade I HIGHLY RECOMMEND equipping the item for now and farming another. The odds of Removing and ADDING are far lower at this stage.
If the Item is not an upgrade try to remove and add the correct stat. I typically do not use gems at this point unless I manage to remove the % damage and the OFF stat this still gives a chance at redemption. Removing 2 Suffixes (damage rolls) Consider it a brick.
Good Enough VS Perfect
Sometimes you manage to get an upgrade at that point ALWAYS take the win.
Eventually doing this it WILL connect for god tier results.