hi, just to give you a quick warning, most (but not all) nikkah only applications take longer than normal time to complete, because IRCC look for a rukhsati being done.
that being said, the
full guide on CIC website is the best resource for help and this forum and the members here are a great resource for help also. if you have question we can give you info or guide you from our own personal experiences. we are not professionals who do this for a living
yes definitely send pictures of your time together before the nikkah, give them the whole story of how you guys met and when, etc. send chat logs, call logs, pictures of you both together on trips, boarding passes, passport stamps of exit entry, gift receipts, etc. for nikkah pics make sure to take close up pics of you both when signing the nikkahnama in addition to taking pics with your parents and with guests. these days it seems better to sign the urdu nikkahnama and then have a certified copy and a translation done of it in English. even though it would make sense to use an english nikkahnama from the start to avoid doing a translation but you will see nothing makes sense with CIC and London Visa Office (LVO).