When I try to play one of my favourite songs, I get nervous when I know that it contains a barre chord, because they sound bad on my guitar.
Other chords sound good.
strings gauge : Extra Light / Action : 0.6
If the strings buzz on the frets when you play the chord you should check a few things:
1. As Tetsujin mentioned in his comment, you might not have the strength to push hard enough. This will come given enough time and practice. You could start by playing a
F chord on the first fret, with a barre only on the E and B strings.
2. Make sure your barre finger is pushing down right behind the fret. The further away you place your finger, the more pressure you need.
3. It can help to slightly turn your hand to use not the exact inner part of your finger, but more the edge of the inner part, closer to the middle finger.
It takes time to get the technique. The best tip I can give if you don't know this already is not to lay your index finger totally flat but to roll it round slightly so that it is the bony side, rather than the fleshy pad of the finger pressing down.
For F shape barre chords there is trick for avoiding them altogether (Jimi Hendrix reportedly did this) - don't barre completely, just barre the B and high E strings and tuck your thumb over to fret the low E string
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I've found that the geometry of your arm, hand, and fingers with respect to the neck matters. Adjusting the neck up or down (i.e. angle with respect to the ground, or your body) to a position where you can hold the bar chord that sounds right, will help.
Do this while not playing a song, until you find the comfortable position. Recognize the neck position may change as you move up the neck.
Focus on getting a good chord sound, not speed. The speed will come with practice.