I can't say enough about how helpful mindfulness can be for surviving the NICU. Here are a few of my favorite practices specifically designed for parents in the NICU. I love these practices, because they are great for increasing your mindfulness and calming your energy while you are spending your time with your baby.
I also love these practices because they can turn a really upsetting time - times when you visit the NICU and you are not able to hold your baby - into a time when you can do something to help yourself. These times can be incredibly frustrating and disappointing for parents. As the nurse, I love to have the family visit as much as they can, but sometimes that means parents show up to visit when it's just not a good time for baby to be interrupted or stimulated. Rather than see these times as frustrations, I hope you can optimize these times by doing some mindfulness practices.
If mindfulness isn't your thing, give it a try anyway. NICU's probably aren't your thing, either, right? This whole experience is going to make you grow, so why not grow personally too? Whether you are holding your baby close to you or not, see if you can use these practices to your benefit while you're in the NICU:
Sit quietly, and take 5-10 deep breaths, focusing on breathing out all your tension. When you feel ready, turn all of your attention to the noises in the room around you. Most likely, there are many. Alarms. Ventilators. Staff conversations. Other babies crying. Other parents talking. More alarms. Background hospital noises. Try your best to just sit, and listen. As long as you can, just sit and listen. Now, notice how these noises make you feel. Tense? Angry? Annoyed? Worried? Hopeless? Try not to judge youself for having these feelings, just notice them. Be kind with yourself - it's totally understandable for these noises to upset you. But during this mindfulness practice, try to let go of your feelings about these sounds and just hear them. Just...... hear...... the sounds. When you notice the feelings associated with the noises, try labeling the feeling ("I'm angry" or "I'm so annoyed") and then let go of the feeling, just go back to hearing. Notice the quiet times. Notice how you feel during those quiet times, and again let go of any judgement about the way you feel. When you notice your mind wandering, let the next noise bring you back to being mindful of only the noises. Notice what it feels like to just be present with all the noises, see if you can use the noises to keep bringing you back to just listening, not getting distracted by other thoughts.
If you are able to touch baby with a hand placed on her back or body anywhere, this practice is easier, but it's not necessary. With this exercise you use your baby's breath, in breath and out breath, as the focal point, rather than your own. This can be hard to do at first, because babies breathe much faster than we do, and you may find yourself hyperventilating to match baby's rate. When you find yourself doing this, just take a nice deep clearing breath and go back to focusing on your baby's breath. Imagine the air going in, going out, imagine it bringing life oxygen to your baby, exhaling the byproducts. In and out, baby is alive, each breath over and over a reminder of life. When you find yourself getting distracted by other thoughts, be kind with yourself and just notice this, and then take another nice deep clearing breath and focus on baby's breathing. Use the time to focus your mind on one thing only, baby's breath, and give yourself permission to let go of every other worry, every other thought, just for this brief time. You'll have plenty of time for all that later - when you're doing your mindfulness practice, give yourself the space and time to just be.
Baby & Me
This is my favorite one, and it can take up a good long time, so it's great for when you have a bit more time to do some mindfulness practice. If you've ever had anyone talk you through a toe-to-head relaxation, you get the idea. Here's what to do: get comfy, a place where you can see baby but you don't need to be touching for this one. Begin from the toes and work your way up to the head.... Focus your attention on baby's toes, just see baby's toes, allow your attention to pause there and then bring your attention to your own toes. Notice how they feel, notice if you end up wiggling them as you think of them. Try to keep your attention just on your toes and your baby's toes. See how they're similar. Imagine how baby's feel. Stay with focusing your attention on toes for as long as you comfortably can. Now, I don't mean just look at the toes while your mind is thinking about a million different things. I mean bring all your attention to just toes, yours and your baby's. That's hard to do, and when you get distracted, just go back to the toes. And then when you're ready, begin moving your attention up your body - notice your ankles. How do they feel? Notice baby's ankles, notice any feelings that come up. Continue in this manner, going as slowly or as quickly up the body as you like.... next the calves, knees, thighs....hips, belly, lower back, upper back.... shoulders, arms, elbows, wrists, fingers....neck, face, mouth, scalp.....
Naturally you may have difficulty at certain places. Your baby may have an IV in a foot, or a tube in her mouth, or in her chest. Your baby may be placed in what looks like an uncomfortable position. When you notice discomfort rising in your mind when you focus on a particular area, be kind with yourself and let yourself feel whatever comes up. But recognize it as just a feeling, know it will pass. Label it, and without attachment place that thought aside and re-focus on whatever body part you're on. When you're ready, move on to the next body part. Because noticing what arises in your mind, and then observing it with kindness and letting it go are all great practices in mindfulness training.
Tonglen for the NICU
We begin the practice by taking on the suffering of a person we know to be hurting and who we wish to help. For instance, if you know of a child who is being hurt, you breathe in the wish to take away all the pain and fear of that child. Then, as you breathe out, you send the child happiness, joy or whatever would relieve their pain. This is the core of the practice: breathing in other's pain so they can be well and have more space to relax and open, and breathing out, sending them relaxation or whatever you feel would bring them relief and happiness. 
Rather than being passive and helpless, this one thing may be something to comfort you and your baby.
I hope these mindfulness practices can bring you some comfort, and a sense of purpose. I hope you gain some relief and some empowerment by actively encouraging your own health and well-being during this difficult time.
[One last thing - if you're worried that other people will talk to you or interrupt your concentration, you can always place earphones over your ears - with music on or not - so that others around you will see that you're occupied with something else. ]