One important thing I ought to mention; every so often scan the body for TENSION and relax it in case its tense, like: hands/fingers, arms, shoulders, neck, jaws, legs, torso ... when there is too much effort on our part jaws, shoulders, arms and hands are the first to get tensed and this can lead to extra agitation. Calming the body is good to do every so often during the sit.

Noting is a fine art. One thing not many talk about when it comes to Noting is the ATTITUDE and MANEUVERING. Its not just about mindlesly noting no matter what but rather developing sense for the terrain thats presenting itself.

Attitude is one of a "Reporter", just like a journalist reports matter of fact from the ground or a reporter on a foodball game. He/She does not take sides but does report in a objective matter of fact manner. Acceptance is another very helpful attitude to remind oneself of during the sit.

Maneuvering is a skill to develop and is "inspired" by the actual mind terrain which WILL keep changing (hey Anicca hows it going). Here its needed to skilfully work the gears of both attention and energy. This one is really trial and errorbut thats all good. 
If its hard to focus and things are unclear then slow down to 1 or less sensation per second and use helping words such as "there is (give time to attention to lock onto something actual) ... coolness in the nostrils as I breath in (or else)" or if its very uncertain that Im noting correctly as all is just so damn fidgeting use word "certainty" each time you label a sensation if indeed you are certain about it and if not use word "uncertainty", like ... "seeing-certainty, ... coolness-certainty, ... unsure-certainty, confused-certainty, ... eye sight blip-uncertainty, etc ..."

When there is lots of sensory clarity things usually have energy to it too so fast noting that can even go into mumbling is fine so one doesnt loose much time on whole words Here even silent noting can work well. I like mumbling as it turns mantra-like which alos acts as a concentartion practice. 

At times one is very sleepy and not motivated; shout out loud the labels and keep a faster pace of at least 1-2 sensations a second. This can bring about the energy. Also do noting aloud while standing. At times I stop focusing on a kasina object if very sleepy and dozing off and rather look throught he window and keep noting the "seeing and comprehanding (that which was seen)". This also help energy to pop out and even gets one very interested fast especially if there is wind outside and trees are moving and birds flying by etc ... ALL THIS IS VALID EXPERIENCE, the same as Jhana or the Itch on the body. All is equaly importantas it is RIGHT HERE RIGHT NOW, the only thing thats trully there. We ofetn hear masters say "This Is It!" This IS IT if Im not embeded in it but seeing it for what it is. Ever changing, not-self and unsatisfactory.

At times one is just way too agitated; "use the voice" sias Shinzen Young. Use the calm voice as it will in 20-30 minutes induce equanimity to the sit. Calm, not too loud and switch the gear to just 1 sensation a second. No need for rush in agitated waters. Here you just want to stay afloat and swim gently until waters calm down. etc ... 

Also, its ok to label 1 sensation and then just notice the next one or two or three if they arise and pass fast without feeling guilty about it. I often notice much more than I label. Its all good. At times I can only note one sensation a second or even two seconds.

Its trial and error but one gets the hang of it if one respects the terrain at hand. Im far away from being a master at this though  

I hope Im not confusing you more with all this!

Agreed Chris!

To riff some more off your comment,

This is a spot where the maps are super useful imo.  If you're pre A&P, fast noting with excellent technique seems just amazing.    If you're post equanimity, it's probably too narrow.  (assuming 1st path)

At some point around equanimity, noting will start to feel weird and constrictive.  You'll automatically begin paying attention to all 6 sense doors in a more panoramic way and it will seem like a lot of pointless work to keep focusing the attention narrowly on the primary object.  You'll be tempted to stop noting and just sit, and you should surrender to this temptation.

There is however a massive shadow side to the above.  Giving up on noting too early is way worse than surrendering too late in my opinion.  Fast noting takes a ton of effort and is quite intense, you'll often be tempted to stop doing it.  The mind wanders away from the primary object constantly in every sit, so if you don't like noting at that particular moment and your mind wanders, you might think "maybe I'm in equanimity and noting isn't right for me, I better drop it and pay attention to all this other interesting stuff," which is a good way to muddle things up.  So, particularly at the time when you're considering changing techniques from fast noting to something more open, it's very important to do some careful mapping and try to figure out roughly where you are.  Did you just go through reobservation and it was almost impossible to sit still and pay attention to anything and perhaps you felt like you were going nuts?  Were you spending a lot of time thinking "If this goes on for any longer I might entirely lose my shit?"  And then fairly suddenly did that all calm down and you're not sure what to make of it?  Probably a good time to consider going for something more open.  Also, there isn't really any time pressure on the equanimity side.  It's fine to stay in equanimity noting away, you'll just end up (consciously or not) perceiving the noting and the attention and all the other stuff in some broader way.  I do think however that at the higher ends of equanimity something too 2nd jhanic like fast noting and very effort forward will make it a lot harder to land a fruition, but that'll take awhile from the beginning of equanimity and should come fairly naturally.  I think eventually regardless of what you think your goals and hard won techniques are that as equanimity matures you'll end up forgetting about them and just naturally do whatever is required; which is not very much.

My personal experience in this territory was soldiering on with my fast noting for like 9months of daily practice in equanimity until I learned how to give up.  Being a glutton for punishment seems to be a bit of a recurring theme for me