they only diy that i ever had problems with that really frustrated me was window tinting, i did it on my first car then after that i swore i wouldnt do it again..not even if they paid me. id rather pay and make it look more pro done.
dont be discouraged, thats how we all learn, from our mistakes. within time the more practice you get the more better the outcome is going to be, especially if you take your time with it.
good luck