I believe out there are people who you can refer to as prodigies when casting. Though before they have reached that stage of mastery, they too have started with the basics. Well, everyone starts there. There will be if not much, no progress at all without the knowledge about what it is one is trying to do and accomplish. That is what you will need the most, along with the proper mindset and patience even if it takes a year or so for results to show.
At the beginning you may find the results of your spells weak, it is the same concept in learning a new instrument. Before you will be able to play it smoothly you will need to practice again and again before you get good results.
Always remember though, that the results will vary depending on your mindset and its possibility. If it is something like Time Travel, you may believe it is real but it is not something that is achievable through a spell.
Yes, Black crow is right, practice, practice and practice again.
Moon Phase, spell ingredients, intention, will all combine to make the Spell come out the way you want it.
To Know, To Will, To Dare and to keep Silent. Keep trying.
Magick use is actually a muscle that you have! The more you use it, the stronger it gets.
Take example your normal muscles. When you go to the gym, you work them out, give them time to recover, keep working them out, and soon enough you are lifting bigger weights, have bigger muscles and are a lot stronger.
Of course, it didn't happen over night, it takes time for them to strengthen and recover. When you started at the gym you were barely lifting 20lbs, but after a month of training, you could be at 45-50lbs!
Your magick muscles are just like your physical muscles! You got to work them out, have some recovery, and keep up with them.
Something to note, the phrase "use it or lose it" applies. Many people fall in and out of practice a lot! (including yours truly). When coming back into practice it's important to take a good week (or until you feel ready again) of energy work and minor spell casting to warm them back up.
It's not like you'll fall all the back down to the 20s (where you started) but you can't pick that 50lb weight right back up.
This is also how there are different levels of spells. Experience in the gym can you get stronger faster and wiser on how to do things.
I think what most people tend to lack in explaining is that magic requires a higher level of understanding than normal activity. To be "good" at magic you have to understand it and be able to envision it at a core level. Read up on magic with at least a few books and meditate on it. Meditate on what magic means to you. Is it organic? Is it energy, or is it a manipulation of energy? Only then can you have any real success with magic. Then practice, and grow an acquired taste to magic. Try everything, and practice it to the best of your ability and do what makes you comfortable.
