it will take some concetration also lots of meditation to channel enough energy to be a good wizird. to also believe magick to be good in spells, knowledge is power to boost up practice on easy spells to improve.
Study, study study and then practise practise practise.
Magic is a science and art, so you need both to spend hours studing and practising as well. Start reading books, they are ussually good guides.
I recommend you the Modern Magick: Elevel lessons in High Magical Arts from Donald Michael Kraig.