I am sharing some tips and tricks with you here, with the experience I have had in programming
# If you are uploading any files using form , always use enctype=”multipart/form–data”  in the form tag.
For eg.   <form name=”myform” method=”post” enctype=”multipart/form–data“>
If you don’t use the above attribute , you will be not able to upload the file onto the sever
# if some of your form values are not submitting, then the first thing you should check is whether the all the elements are lying with the <form>
and </form> tag . Sometimes the form tag structure look good but the tag structure does not form well , when the DOM creation take place ie the page rendering.