Hi MsRuby, Miss D. gave you a great link; however, do not stress if your package does not look exactly like that. For sure, do the forms online as the bar codes speed up processing. Also if you can pay all the fees up front and online, do it, one less item to leave in POS hands for follow up. No staples, use paperclips.
You can do either with the photos, I had multiple sets of our wedding photos as I knew we would have to send one with our app. but for some prior years, I just did colour photocopies. Actually we did not even have a camera for the 1st 3 years of our relationship so I only submitted about 40-50 photos in total and it is important to label or write on the back, who is who.
I also created a word document with a selection of SKYPE messages and e-mails (copy and paste) some from every month we were together to show progression, and details of SKYPE call durations, which I highlighted. Because we have been together 6 years I thought including every single thing would make an unwieldy application (for them and us!!) and I said so in my explanation paragraph that I included at the beginning of the word document.
I did not include any phone bills as we have used calling cards for 6 years and they do not accept used calling cards anyway and most people dispose of them. Again I explained this in my application. I think the most important thing is to explain the rationale behind any decisions i.e., we did not honeymoon as we did not have the time or the funds and used that money on the medical and immigration fees!!
Of course I had all of my travel documents from every trip, all receipts, all visa bills etc. but aside from the word document I did not include any additional pages and answered all questions in the space they provided on the application. Which is to say I was unusually succinct. Do not send original cards, if they want to see originals they will ask and you do not want to send keepsakes that you may or may not get back.
In my application I told them that I had 6 years worth of everything and I would send them more if they wanted. They obviously didn't though so that was great! Blessings.