well props for believing if at first you don't succeed, try try again, but you might of benefited from asking for help three and a half years ago.
firstly, what spells have you been casting exactly? the spells on this website aren't the most reliable as the majority are non-working spells. you can pretty much rule out any spell in the Fantasy or Trick sections as they don't work [hence the category titles] so if you've been casting transformation, teleportation, levitation, invisibility, or anything you saw in a movie, chances are that's your problem.
you should study a bit of basic information and figure out what magick is and what it can and cannot do. real magick is a neutral energy found in nature. being a part of nature it cannot contradict nature. also, being an energy it can effect energy, not physical things. [a love spell works by manipulating the energy around a person, while a spell to make yourself into a vampire would not work because you would have to manipulate your DNA] there are many great books on the subject, but if you cannot afford or acquire books, you can read a couple articles on energy, magick, and energy work [such as charging, grounding, centring, shielding, and psi balls]
now, lets say you cast a spell from one of the working categories and it still failed, there's a number of reasons why.
energy you didn't charge energy, or enough energy. you might also of relied on your bodies energy which is a bad thing to do as your body needs this energy to funtion and you could get sick. try some basic charging and grounding to get a feel for the flow.
focus it's wise [but not mandatory] to meditate before a spell because it will calm you, clear your mind, and put your mind into a focused state to cast the spell [some also use this time to charge energy. it depends on the caster] to cast a spell you need to focus the energy and give it a destination point. if your mind is going 'bring me money... bring me money... did i have homework... bring me money... i'm hungry, i wonder whats for dinner... money... is that my phone?' the spell will have gaps in the energy and weaken the spell.
visualization kind of hand in hand with focus, you should try visualizing your desired outcome like a photograph or video so it feels 100% real and plausible to you. if you let your mind wander, again, the spell will be weakened.
procedure sometimes you get the above points correct, but a spell still falls short. it could be either the spell itself is flawed, or you miscast. if it's the spell, research the ingredients to be sure they all work in the spell, there could also be too many items. a common problem is [like focus] you didn't try and memorize the spell. if you're meant to focus on the spell, you can't keep stopping to read the next step, or stumbling over lines in a chant. sure, we all get tongue tied and our minds go blank, but if you go 'place clover in cauldron. next step... light candle. next step... chant money... money.. shower...' you will loose focus and the energy will weaken, the spell will weaken, and you'll probably need to recast the whole thing.
moon phase this one is a personal belief and by no means fact, but many practitioners cast by the moon phase. like with the tides the moon can push and pull energy, so certain times it's better to cast certain spells. the waxing moon [new to full] is a good time to bring things to you [luck, love, wealth] while the waning moon [full to new] is a good time to send things away [break a bad habit, banishing an ex, weight loss] as you get better with energy you should be able to feel the energy during the different phase and draw your own conclusion.
intent intent is also very important. if you're casting because you're bored, practice, or an experiment, there's a good chance it won't work. magick is best done when necessary not for fun. sometimes an unexpected bill pops up, sometimes you want to take a trip, on these rare occasions a wealth spell is a good idea because it's needed for your well being. granted, sometimes the universe/Gods [whatever you believe] will hear your request and say 'no. you can't pay your bills because you spell all your money on stuff.' and refuse to help. but if you only cast when spells are needed, you should see a higher success rate. [if you want to practice spell casting, practice energy work, meditation, and visualization, get these down, and you're set]
of course, for all you know some of your spells did work and you just didn't realize. magick is subtle, so you might cast a money spell then sit back and expect to be handed a million dollars, but what happens is you're offered more shifts at work. the spell did work, just not in the way you expected. you should keep an open mind.