Saving data from a modelform Django

Now heads up! I am fresh noob off the NOOB-BUS from NOOBSVILLE!

So i am workin on a form to load up information and edit that form information and im in a headache. so i am using:

Django: 1.8 Pyhton: 3.5.1 backend is sqlite

I am using a form.ModelForm to load information into but when it comes to saving this is where i am stuck. the documentation is very confusing should i use all or just one clean.

this is the forms.py

    class EditContact(forms.ModelForm):
    class Meta:

    model = Contact
    #the list of all fields

    exclude = ['date_modified']


    def clean(self):
        if self.date_of_entry is None:
            print("looking to see what works")
            self.date_of_entry = datetime.date.today()
            return


    def clean_ContactID(self):
        #see this line below this comment i dunno what it does 
        ContactID= self.cleaned_data.get('ContactID')
        print ("cleaning it")
        # i also dont know what validation code suppose to look like
        # i cant find any working examples of how to clean data
        return ContactID

now there are mainly more def clean_methods but i think what i want to use is clean which should use all but in my view.

this is in view.py

def saveContactInfo (request):

    #this part i get 
    if  request.user.is_authenticated():

        ContactID= request.POST['ContactID']

        a = ListofContacts.objects.get(ContactID=ContactID)


        f = EditContact(request.POST,instance=a)       

        print("plz work!")
        if f.is_valid():
            f.save() 
            return render (request,"Contactmanager/editContact.html",   {'contactID': contactID})
        else:
            return HttpResponse("something isnt savin")

    else:
        return HttpResponse("Hello, you shouldnt ")

and this is model.py

 def clean(self):

    if self.ConactID is None:
        raise  ValidationError(_('ContactID  cant be NULL!'))

    if self.date_of_entry is None:
        print("think it might call here first?")
        self.date_of_entry = datetime.date.today()
        print ( self.date_of_entry  )

    if self.modified_by is not None:
        self.modified_by="darnellefornow"
        print(self.modified_by )

    if self.entered_by  is not None:
        self.entered_by = "darnellefornow"
        print(self.entered_by )
        ContactID = self.cleaned_data.get('ContactID')

    return

now above the model has the fields and the types which all have blank = true and null = true except for the excluded field date_of_entry

and ive gotten to find out that when calling is_valid() in views it calls the models.clean() but it fails to save!!! and i dont know why! i dont know how to do the validation. i would like to know the process and what is required and even an example of form validation a field.