nice explanation
so what your going to learn first is how to block and evade it
so there are many types of genjutsu, aas you talked about the sharingan which is a visual type
then there sound type gen, elemental and many others, but remember gen always works by manipulating your senses
so to block or evade them one must be capable of predicting them so to block that sense thats being targeted, but since thats very hard what you can do is repel it
ways to repel gen jutsu are:
pain and kai
depending on the level of gen the pain you must suffer to escape genjutsu is varaible so it can go from stabbing yourself to making a really big injury
as for kai that demands chakra control, ill explain this properly later