Don't worry so much about the spells you cast. If you think too much about them the energy you emit from that disrupts the processes working around you. If it happens, it happens, if it doesn, it doesn't and you move on. Keep studying though, Adriana is right, make sure you understand how spells work before you ever expect to get anything out of them.
Ok this is sort of hard to explain especially because I don't know you but you can't just chant a few lines, light some candles etc. and expect a spell to work. YOU have to do something to kick start it. And that something you do is something that is purposeful and meaningful to you so because I don't know you I don't have any suggestion but for example if you adore art or you're good at it then paint or draw a visual representation of the spell. Or maybe if you like music, you don't even really need to be able to play an instrument well but play a piece that is meaningful to you and an audio representation of the spell that you can put your whole self into playing. There are a lot of things you could try but thats just some suggestion