I think that any personal archive of the sort that you have put together is of potential interest to future historians – the fact that it ties in with materials you have been assembling for some time and that it covers a variety of different themes, in particular, makes it more valuable than records that are less comprehensive or cover briefer durations – so perhaps the first piece of advice I can give it to keep going for as long as you can.

I'd add that for many historians what makes a diary and associated documents especially useful and important is that the diarist develops a "voice" – in other words, that readers should hear not only about what was happening (and perhaps especially about the things that you and the people around you thought were important, or transformative, or in need of preservation) but also what you thought about it, and why. Diaries that tell us something about these things, and yet also offer us insights into how these attitudes and opinions fit (or don't fit) with those held by other people at the same time are of particular importance, so I would suggest thinking in terms of placing stress on this side of your project – what tends to happen is that historians have reasonably good access to the sorts of artefacts you mention collecting or collating, but much less idea of why they mattered to people or how exactly they were used. These are certainly the reasons why some of the great diarists, such as Pepys and Channon, are still widely read today.

You may think from this reference to two diarists who were senior officials in the English/British state that it is important to be part of an elite, or have access to its gossip. I can't pretend that doesn't make a difference to the chances of anything you are doing surviving and being used for centuries, but in the course of the past century a significant tradition of more "everyday" people writing invaluable accounts from more local or specific perspectives has grown up here in the UK, nurtured by a remarkable organisation called Mass Observation. This encourages people willing to contribute regular diaries to compile them and submit them for use by future generations – it's worth noting that MO has learned that it's best to direct its contributors' efforts by publishing regular "directives" that suggest topics that it would be useful to write about.

The Institute of History has an interesting overview of why the MO archive is of great value (and hence how you may better assemble materials of use to future historians) that you might like to check out, here, and there's an interesting reflection on why one of the best-known of their diarists, Nella Last, wrote material of such great value by the archivist who curates it, here. Good luck!