I'm not trying to be rude when I ask this question...but have you learned the basics of magick?
If not, I would suggest that you should start there. Here is a link to the SoM Survival guide...you should read it all but especially the second part of it.http://www.spellsofmagic.com/read_post.html?post=329074
So..are you effective with your meditation and visualizing skills? Do you know your correspondences? When you are raising your energy can you feel it strongly?
If you haven't answered yes to all of these questions then you really need to spend some time developing these skills.
One other thing, it is always better (in my opinion) to write your own spells..who better than the person with the need..you know exactly what it is that you want...it doesn't have to be elaborate...just come from the heart.
Also, I don't know what kind of spells you are referring to when you say they won't work..but there are some things you cannot change with magick, and somethings don't need magick...some things just need to be left alone. I am also compelled to mention this: make sure that any spell you do harms none and it is also my recommendation that you not try to change someone's free will. Just a little ethics here.
As well as the validity of the comments above, (wise words), you need to know that, if you are choosing spells from this site, many of these spells are fantasy, and will never work. Try to use some common sense and logic when choosing your spells. And, practice your basics! :)