Some excellent suggestions here that I completely agree with, especially the nasal aspirators and first aid kits - so important! I'd also emphasize the importance of a good, sturdy, and comfortable baby carrier. With two little ones, you've got enough on your plate, so having a hands-free option for a walk around the neighborhood or just to keep them calm is a God-send.
Having a solid routine from day one is also helpful, as it gives you a semblance of control and prepares the twins for what's to come. Establishing a feed-play-sleep cycle helps to keep everyone on the same page and provides some structure to your day. Of course, it's also vital to have an open mind and be prepared for when things inevitably go awry - because they will! - and that's when all that accepted help comes into play.
On a personal note, I also found that keeping a small journal helped me keep track of their feeds, nappies, and milestones, especially in the early days when everything was so new and chaotic. It gave me a sense of accomplishment to jot down their achievements and provided some clarity amidst the fog of parenthood!