I can't tell why this isn't working...

Is there a way to add a de-bugging method to the trigger to see what is happening? 

How do I know if the first few definitions (particularly of the list "list_relatedstudents" isn't null after I try to define it; then when I go to update the list with "update list_relatedstudents" nothing happens)?

trigger Bulk_CallLogs on Student_Call_Log__c (after insert, after update) { list<Student_Call_Log__c> list_thelogs = new list<Student_Call_Log__c>(); // list contains all of the logs being processed // Step 1 set <id> list_relatedstudents_temp = new set <id> (); for (Student_Call_Log__c log :list_thelogs) { list_relatedstudents_temp.add(log.related_student__c); } list<Student__c> list_relatedstudents = ([select id, Most_Recent_Call_Note__c, Tech_Support_Logs__c, Call_Count__c from Student__c where id IN :list_relatedstudents_temp]); // Step 2 list<Student_Call_Log__c> list_relatedlogs = ([select id, related_student__c, date__c, note__c from Student_Call_Log__c where related_student__c IN :list_relatedstudents order by Date__c DESC ]); list<Student_Call_Log__c> list_relatedlogs_mostrecent = ([select id, related_student__c, date__c, note__c from Student_Call_Log__c where related_student__c IN :list_relatedstudents order by Date__c DESC limit 1 ]);