AUDIO RECORDING - SOME BASICS 
Audio fills in a lot of the mood of your video. It provides atmosphere, but also helps propel the story forward in basic terms, making it easier for the audience to understand what is going on. Sound effects, well placed, can make a big difference in the impact of a sequence, music can boost mood like crazy, but the biggest upside of good sound recording quality, the best reason to try to do it right while recording and not just in post, is that you can hear the dialogue and don't make the audience awkwardly strain to make sense of the story. So clear audio is valuable. It is worth it, because I know from experience how much bad audio can screw up your otherwise potentially entertaining dialogue. 
 
I'm a big fan of shotgun mics, I've used them on many of my videos over the years. They're fast to set up and easy to move, they can be mounted onto many types of cameras, and this is all great, because my work is often ridiculously hectic and lavalier mics simply are not worth the time it takes to set them up in my view, certainly not appropriate for my rapid-fire 'run and gun' videography style. Get a shotgun mic that's good enough to capture clear sound, if possible, and if you are recording outdoors it's advisable to have a windscreen (a foam one at minimum or ideally the fluffy type that people in the biz call a 'dead cat'). Attach the windscreen to the mic, the mic to your camera, which means getting a good video camera that has a mic jack if that's possible. As a low-budget indie, I'll admit I now have a camera with great video quality but average built-in mic and no mic jack. It makes things difficult. I can, however, run a good mic into a mobile device (a tablet or phone running a voice recording app) and dump that onto any available surface near the project that is going on, carry it with me or whatever. The upside of this is choice - if the audio on your camera sucks on a given shot, you'll have a backup that can be aligned to the main track. Works well especially on the VFX shoots I tend to do, where there's a big chunk of video all in one room. 

The reason those clapboards exist in Hollywood is that firstly they identify the scene and shot number of any given segment of recorded video, but they also make a brief but loud 'clapping' motion and noise right after the camera starts rolling. Why does Hollywood do that? Well, it's so there's a sound and visual that can be used to accurately align audio and video tracks if they're recorded separately. I don't personally see the need for the clapper - I just use the audio built into the camera most of the time, and shout 'action' as an audio reference point and swap in a secondary audio segment with that sound used to align the audio in Track 2 with the audio recorded by the video camera. It's simpler but it works. I've dubbed a reasonable amount of audio over the years, often like this. Heck, I even went dub-crazy on the video 'Super Soda' in 2006 because the microphone failed for a sizable chunk of the recording process. Rather than rerecord the video, which was not possible, I focused on rerecording and aligning the audio as well as I could. If you do dub, let the actor see both the line and the original recorded clip in an effort to match the pacing, but know that editorially you can speed, slow, and slice/dice the sound patterns in modern editing software, cutting out dead space between words or parts of a line. The result in that case wasn't flawless, it still didn't line up perfectly, but better a bit of misaligned sound than words you can't make out, like in the awful audio in parts of the third and fourth 'Send in the Clones' or the sound in certain parts of 'Troop 4 TV Season 3'. I wish I could have dubbbed that after the fact too, but there was barely enough time with the cast members to shoot everything once, much less rerecord the dialogue! 

Here's a fun sound trick - using a directional shotgun mic (directional mic is best mic!) you can minimize distracting sounds behind the actor by aiming the mic at the actor from below. That way it captures the voice and everything above it. Or aim downwards in the direction of the ground, if air traffic's an ongoing intermittent problem. The only other real trick is a common sense one, which is get the mic as close to the actor as you can so it gets more detail in the sound and less of the surrounding noise. I so wish I'd done this on Troop 4 TV: Season 3, because the camera and mic were a bit back from the red screen - yes, a red screen, because the actors stupidly wore blue, green, and white clothing in the main shoot and the VFX shots had to match that - and the AC in the building could not be turned off, which resulted in an obnoxious hum all the way through the shoot. It not only interfered with the voice audio, but it could not be fully separated in frequency from the sound of the dialogue. I ended up cutting the hum sounds by about 60% so they were less obvious but not removing them entirely because the rest of the dialogue sounded bizarre and not quite human, with those portions of the sound completely excised. But that's just an example of the Murphy's law nature of video recording. If you can turn off interfering sound sources, do so. In that case, we couldn't. Remember to have plenty of battery power on camera and mic and spare battery and storage media for everything, so everything does not grind to a halt halfway through the effort. Also, the rule of getting the mic close, is mirrored by the rule to do the same with the camera, just move it close, if you want a close up. Get the camera closer, instead of zooming. Optical zoom won't kill video resolution but it will amplify every shake and jitter exponentially, particularly problematic if the camera's handheld. And as for digital zoom, kill it with fire. Seriously, digital zoom is garbage, it rapidly erodes video quality the more it is used, and it should never be used ever. 
 
Finally, keep in mind that there are many music clips and sound effects files available online, which can be integrated into your edit. Some are free, some cost money. The free ones often require attribution, which means mentioning the creator of the track in your credits. That's fine. Do some online searching and you'll find some good sources for sound effects and such.

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