Hi buddy ,
I'm attempting an requirement ,where  an email notification to the sent to the opportunity owner 90 days before the contract end date. Few conditions which are to be followed.Their are two picklist field "Status Renewal" and "Status Renewed next year" .Contact role is a custom object which has "role" has picklist field and has a lookup relation with contract .

Condition to be given is :
a)"Renewal_Status__c" is equal to pipeline ,next renewal status And
 b)when the "Next_Quarter_Renewal_Status__c" is not equal to renewed ,renewed lost.
 c)Contact Role equal to sa/ra/ta.
Once the condition is satisfied , then the email notification is sent to the opportunity owner ,keeping in cc to the contract owner.
Now , if we get the response from the customer for the renewal ,then an update is done by the owner  updating the "send renewal reminder".
We have a picklist field as ''send renewal reminder" with yes or no values..Their few more condition now.
Condition 1:
If the "Send renewal reminder" is "YES" then an email notification mail is to be sent to the customer for 45,30 and 15 days .
for this there are few condition to be followed .
.i.e  a)"Status Renewal" is equal to pipeline ,next renewal status And
b)when the "Status Renewed next year" is not equal to renewed ,renewed lost And
c)"Send renewal reminder" is "YES".

Condition 2:If the "Send renewal reminder" is "No" ,then stop sending the email notification .

Condition 3:If the "Send renewal reminder" is not updated ,then an email notification needs to be sent to the opportunity owner and the superior for 3months.

How can i achieve this ?Any Suggestion or examples very much appreciated.