Even if you don't plan to run Iron Banner on a specific day still pick up the bounties (3 Gold Weeklies and 3 Green Dailies) so they are there ready for when you are going to run Iron Banner. If you also have any of the Iron Banner specific gear like Emblem, Shader, Class Item then make sure they are equipped when running Iron Banner.
If you have multiple characters then get your main to rank 5 as fast as possible as the other characters will get bonus xp and you can get them to rank 5 fast. I think it took me over 50 games for my first character and my third took me 13 games and only having to cash in one gold bounty.
I personally prefer to run IB over the weekend and grind out all three characters (and then some more from fellow xbox players - I have done at least 5 characters for each of the last 2 Iron Banner Events)
You can only hold 3 IB dailies at once though cant you? Either way, they are usually cleared pretty quickly. I haven't had any experience of multiple characters as i started my second character last night and he is only at 6 right now.. I'll bear that in mind for the future though.
I still have a weekly from the most recent IB that needs cashing in that i never finished. (Special kills were lacking) Will this be able to be cashed in on the next one do you think? Obviously saves me some work then.