Changing Chords

Practice, practice, practice, it will come to you, give it time.  May I ask, how long have you been playing?  What chords are trying to learn?  We have all been where you are now.

thanks and i know all the basic chords by heart and the chords in the song i want to learn are c d g and i know them but i switch slowly

                                                             there they are bluejeep

A little practice tip if you are looking to play C D G faster try thinking the word "change" on the last beat of the bar you are playing before changing to the next chord, in other words think ahead  if the song is in 4/4 count 1  2  3  change  1  2  3  change this will help you play the next chord on the 1st beat.  A simple progression would be 
                                                                                C  2  3 change   D  2  3 change   G  2  3  change  D  2   3  change and repeat
This will help your tempo, chord change and making the chords clean there is no need to stare at the chord you are on and wait look ahead to the next chord you have to play and thinking "Change" on the last beat of the bar will buy you the extra time to do it

any thing that will help with bar chords

This is where an electric is better LOLOL  Ill pound that drum for ever. Electric and Barre chords are like PB&J they just go together.

As everyone has said - PRACTICE - PRACTICE - PRACTICE - is what is needed to speed up chord changes. Start slow and develope the changes between 2 or 3 chords until you have them perfect. Even if it takes all night, Look at the chord fingerings. There are chords that if made with the middle, ring and pinky fingers will speed up the change to the next chord. And this is the MOST important piece of advice I can give you. When changing chords NEVER stop your strumming hand. Your strumming hand controls your timing for the song you are playing. So what if you hit a few open strings when changing between changes. Thats better than not keeping the song in rythem. So when you practice the chord changes and finger placements keep that rythem hand going.

Nela

Something I think is important is posture. If you are standing, find the most comfortable position to hold your guitar. You should'nt have to low or you find yourself supporting it by the neck, it needs also to be angled right so that your hand can move freely up and down the neck. If seated, and this is what I do, don't slump over the guitar or you'll find that your hand tends to slide round the fretboard, your index finger isn't flat and the result is muted notes especially the high e. As everyone has said it's all down to practice. The main thing is, enjoy it, you'll get there

One thing nobody has mentioned yet is about string choice and hight all my guitars including acoustic have light strings and low action which makes such a difference to finger pressure when playing my only exceptions are my two resonators and my stratocaster which I use for slide these are set higher and have heavier strings .Ok light stings on an acoustic Will be quieter but as I only play amplified thats no problem

I cant say much more than the guys have. Practice those chord changes over and over and over and over.  You WILL get faster!  We are all living proof.