Record the family's collective feelings or warmth and belonging for future generations. Naturally, by the time you have planned the above, your responses will have arrived. Start to fit the pieces together and resolve any inconsistencies before you begin to formally compile. This will help you shape your annotations. When loaned photographs have been sent to you, you may be amused to find pictures of yourself or of your immediate family which you did not know existed.
Enlargements are an excellent idea.
I should point out that, despite the best intentions, some family members will either not respond to you at all or will be hostile toward your efforts. It is an inherent risk in any family history effort that unpleasant memories of one type or another may be stirred. Others, however, will be delighted with your endeavors and will provide you with unexpected help and support. These are the people you will want to consult concerning any discrepancies, additional ideas, and so forth. You may also have the pleasant experience of hearing from, and getting to know well, relatives you have never met.