I’d take all of the advice above plus :
Magik is like a muscle you need to train it
How do you do that ? By having succesfull spells/evokation,…
The more you’ll get little victory the more your believe system will shift on it’s own and the more conviction you’ll be able to put into each different kind of work in magik
And a day in the futur a little sentence will be able to bring you whatever you want.
I’m not at that stage tho but comparing my old self with where I’m standing now I’ve made progress that make me feel like I’ve 1000% improved wich sounds like a lot but at the same time magik accuracy starts really low at least to me it has
So in exemple by training my magik/sense/blahblahblah I could have come to an average of 0,1 % boosted to 10% accuracy as for now
Don’t mark my word and make me accountable for what I said I get those numbers out of nowhere it’s just an exemple 
To resume : start in more easily influencable thing and build from there
A thread of mine that I used just for that purpose is : What about this ? Orrr That? Evokation BOOTCAMP
Keep an eye on it because as time goes on the list will grow and maybe some people will start to include their experience as I do
Edit : I have other little thing/success to add in that thread, I just want to fulfill my offerings for each success first before making it into the thread