Getting good audio can be very difficult. Generically you are limited to the quality of microphone you are using. People with good sound have purchased a good microphone such as a Blue Yeti. If you are using your headset microphone the sound will usually be thin (no bass) etc.
There are several types of mics. There are also different sound pickup patterns associated with microphones. Electret, Dynamic, and condensor are microphone types. Cardioid and omnidirectional are the two main types of pickup pattern.

In the chart zero degrees is the area the microphone is pointed at. As you move off to the side or back the sounds volume will change and possibly be colored (change tone). Cardiod patterns try to reduce unwanted sounds from the sides and back of the mic. Omni picks up sound well from all directions.
The best sound for streaming would be a good condensor microphone. It would also be great if you could choose different pickup patterns. This is why the yeti is so popular. You plug it in and you are good to go. Sounds good and has selectable patterns. GG.
Headset microphones usually are cheap and thin sounding. And have very directional pickup patterns so your voice volume will change a lot depending on where your mouth is pointed in relation to the mic. Again, a good condensor will be less directional and more towards an omnidirectional pattern. So your volume will not fluctuate as much. Trade off being the more omni it is, the more keyboard and mouse sounds you will be picking up.
Next up is setting your volume. You never want to be able to speak into the mic and have the sound be so loud that it distorts (overdrives the amplifier). Like when some RNG plane lands on your whole army and you start screaming that Relic is anal cancer! The screaming will be distorted. You also dont want most of your speaking to be too quiet then destroy the listeners ears when you start screaming. A constant volume is what you are aiming for.
So you need to set the volume so that the loudest sound you ever make will not overload/distort. And you need to set it at the first gain stage. On some mics you can set the volume manually right on the mic or its USB cord. On most you need to set it in windows at the recording devices dialog.

You will have more volume reducing options later but they will not help you if the sound is already distorted. You need it reduced at the source!
The dialog may have a VU meter or volume graph. You will want to make the loudest sound you will normally make and never max out the graph! In this example adjust the volume so you never have all of the green bars lit.
You should now be able to use OBS etc. However, you will still find that your volume changes a lot when you speak. The next step is COMPRESSION. Compression automatically monitors your volume and changes it when you are getting too loud. In OBS you can add a FILTER to your mic source.

The default settings are decent. I Like to run closer to the example settings above. The important setting is threshold. The compressor does nothing until you are talking loud enough to hit the threshold volume. Then the compressor begins to work and reduces your volume. Ratio is how much will it turn down your volume after you are too loud. 6 to 10 is a good number. Too much and your loud parts become quieter than your soft parts and you get a "pumping" sound.
Since the compressor is now turning down your volume to keep you at a constant volume, your overall volume will be low. So you need to adjust the OUTPUT GAIN to bring the overall finished volume back up to the level you want on your stream.
Another side effect of the compressor is your noise floor will now be increased by the OUTPUT GAIN value. So if your mic is noisy (lots of hiss and background noise) it will now be even louder. So now you will want to add another filter such as the NOISE GATE or NOISE REDUCER. These filters are the opposite of the compressor. They turn your volume off until you start talking. Then they turn it up. This means less hiss and background when you are not talking.
When you pick your final volume you should be aware that sound adds. So if you have your mic at MAX possible volume and then COH2 is making sounds, you will overdrive and distort. So you want your final volume around -3 to -6 dB depending on how loud your other sounds sources are (game, music, etc).
The main thing you need is EQ at this point. Most USB mics and headsets will not give you any EQ options. That will give you the ability to boost the bass and try to fix that thin sounding mic.
There are several options to you from $30 to $3000.
OPTION 1: Low as $30.
Cheap headset. Done.
OPTION 2: Low as $50. Usually more like $100.
Decent USB condensor microphone.
OPTION 3: $150 and up.
There are some kits you can buy that will have a normal condensor mic and a USB preamp. This gives you slightly better quality of sound and may be useful for sounds external to the PC (guitars, keyboards, Xbox, etc) The Tascam Ministudio is a device dedicated to streaming and are usually around $100. The USB preamps usually offer no EQ capabilities. If they do, the EQ options may reside in a program that you need to run from them.
OPTION 4: $500 The big boys.
This option gets you to a mixer. You need a normal condensor mic. The mic plugs in to a mixer. The mixer has manual bass and treble controls, additional inputs, VU meters, etc. This gives you the most flexibility. You then will want a standalone compressor/gate. Then a USB preamp. With this setup you should be able to achieve pro level sound. Some companies may have a compressor built into the mixer. Behringer has some offerings as an example. However the compressor has little flexibility and no noise gate options. A seperate mixer/compressor option also has built in headroom so that you are much less likely to ever distort the sound.
Next is just good speaking habits. Watching a pro like Stormless you will notice he keeps a good distance from his mic and never changes the volume of his voice. As opposed to AE who is enthusiasctic and screams HOLY MOTHER OF GOD once in a awhile. Stormless never distorts and doesnt even need any compression. AE seriously needs loads of compression.
You dont want be so close to the mic that any head movement cause drastic volume changes. You also dont want the mic far from you or it will pick up background sounds and more importantly pick up echoes of sound in your room. Too far away and you may sound like you are in a toilet. To close and your volume will be all over. Physics also dictates some bass boost when you are too close to the mic (proximity effect).
You will need to play around with distance to your mouth and also the mic placement and direction. To get the best sound without echo. The echoes will also mix with your voice and cause the sound to be thin because the sounds are out of phase and cancel each other out. So closer is always better until it is not
You will also want some form of windscreen for your mic. Your breath across the mic will make nasty sounds so usually a foam covering is used to reduce this sound. Pros have windscreens that attach separate from the mic.
Here is an example setup from the web:
Also notice that this microphone is being suspended to reduce vibrations. Most condensors will have this type of mic mounting. A Blue Yeti does not, and will pickup vibrations from you touching the desk, typing, clicking, cars going by, etc. You can always fold up a towel and put the yeti on top of it to uncouple the mic from the desk/table you have it setting on. Be creative or spend some cash its up to you.
TLDR
Get a Yeti.
Hopefully some guys will give you some example setups they use and how they set their software. If not I would guess a good condensor mic like a yeti and look to see if they have software that goes with it that may let you do EQ etc. There are a ton of off brand setups on Amazon. Mics and speakers are weird because cost does not always equal good sound. Read lots of user reviews before purchasing. Some $25 chinese knockoff may be all you need or maybe a $500 Rode is what you want.
This field is changing daily as manufacturers are balancing giving you what you need and making you pay a lot for the separate pieces. Why give you an all in one solution when they can make you pay for each piece. The Tascam miniStudio is a step in the right direction. The cheap Behringer mixers that have USB and compression are another. They are just not quite there yet.