No matter what kind of fishing you're doing, you want to be in tune with what's going on at the end of the line. Streamer fishing is obviously no different. Because of where I live and simply my personal preference, I just love to fish streamer flies. Although they are probably the easiest flies to use much of the time, I still see some mistakes being made when folks are fishing them. Not only can these mistakes prevent the fly from being fished properly, but strikes can also be missed. Remember, just because you're streamer fishing doesn't mean every bite is going to be the rip-your-arm-off type. When you have control of your fly and have at least a pretty good idea of what it's doing at all times, you'll be able to fish the fly more precisely, feel more strikes, and thus catch more more fish!
Some points to consider for better awareness when streamer fishing:
Rod tip/line angle-- Slack line between your rod tip and the fly is a great way to miss a strike. Granted, sometimes the line may have slack and the rod tip may have to be elevated such as when mending, but the very best way to feel even the most subtle grab is with the tip low and line straight. While river current may help remove slack from the line, the issue of excess slack really becomes noticeable when on a stillwater.
When fishing somewhere with no current like a lake or pond, holding the rod tip well above the water can cause a lot of excess slack to hang down off the rod tip. This slack lessens the direct connection to the fly and is also more susceptible to getting a bow or big U blown into it from the wind. In addition, each strip of the line causes the rod tip to bounce which is not just annoying, but momentarily dulls feel.
For the best possible feel, keep the rod tip angled down very low to the water and pointed right at the fly line's path. With full-sinking lines, some folks will even dip their rod tip under the water's surface for an even deeper retrieve. A low rod angle will give you a straighter line path to the fly which equals better feel, more exacting strips, and more efficient hook sets whether strip-striking or using a traditional hook set.
Gloves/Stripping Guards-- I can't recall anyone making too much of a fuss about this, but I absolutely can't stand streamer fishing while wearing full-fingered gloves or a stripping guard. I totally understand—it's nice to protect your digits from biting cold or line burns. For me, though, I want maximum feel, so for as long as I can deal with it, I fish with a bare stripping finger.
I feel very disconnected from my fly with anything between my stripping finger and the line. I can't even tolerate something so minor as just a simple band aid. From getting a soft strike to fouling on a tiny piece of weed, I want to be able to feel every subtle thing my fly is doing out there. Sometimes a tiny weed on the fly will barely be discernible, so if feel is dulled even slightly, it may go unnoticed. Everything just feels so much more intuitive with line-on-skin contact and I feel like there's very little that will get past me.
Now, that's not to say I never wear gloves—I certainly do! When it's finger-numbingly cold out I have no choice, but I do wear an old pair with fingertips that fold back out of the way which helps a little. In milder temps, I'm a huge fan of wearing sun gloves for UV protection, however I seek out ones with a short index finger that will not block my feel of the line. Some sun gloves are made with an elongated stripping finger which I totally avoid!
Leader/Fly Line-- With streamers, a short leader is often the norm with a sinking/sink-tip fly line. A shorter leader gets the fly down quicker on these lines, is less hassle to construct/cast, may stretch slightly less, and won't swing around so much in current. Won't that short length spook the fish, though? That depends, but in stained water where streamer fishing happens a lot, it's not as big of a deal. The larger size and more animated action of many streamers commands a lot of attention and kind of "distracts" from the line/leader anyway, plus the ends of sinking/sink-tip lines are typically pretty dull in color to be more stealthy.
You can even upgrade your fly line to one with lower stretch which will improve sensitivity. I recently did some quick testing of one such line, a WF5F RIO InTouch Gold, which is built upon RIO's low-stretch ConnectCore. The difference over a typical fly line was drastic and is definitely noticeable on the water as well.
Focus-- I can't stress the importance of focus enough. It can be a grind to stay attentive after hours of no action, but when you're asleep at the rod is often when a presentation will get screwed up or a strike will occur. Sometimes I swear the fish are waiting for an angler's focus to drift off—I've definitely been caught before when I wasn't quite all there.
While unavoidable fatigue may set in after a while which can dull overall awareness, I still do my best to focus as much as possible. Even if I'm feeling half dead, I'll always keep my rod angle proper and fingers securely touching the line at all times. Another thing I like to do if I'm fishing a floating line or even a short sink tip is to watch the very end of the line. In my streamer fishing I don't find it extremely common, but there have been times I've seen bites before I actually felt them. An unnatural tick or movement of the line on the pause between strips can mean a fish just inhaled or missed your fly.