But before we begin, it is important that see the colour wheel, the kind we used in school to know primary colours, contrast colours etc.
Use the colour wheel like a normal wall clock and then see the colours opposite each other like say a 12 and 6 on the clock and see the colours there. Now these are contrast colours. Popular contrast colours would be red and green, orange and blue, purple and yellow etc. Now these colours you can use together beautifully without worrying about whether they'll match or not. The trick is to look on the exact opposite side of the colour wheel like 3 and 6, 8 and 2 etc.
Using the colour wheel like a wall clock again, find colours that are in the same family. For instance, look at your colour wheel at 5 and 6 and you will find blue-green and green paired together. Now this is a great combination, you must have seen it at weddings in peacock coloured lehengas and ombre salwar-kameez. The other colours that fall in the same family, next to each other on the colour wheel are yellow and orange, blue and violet, green and yellow etc. The trick is to the number right next to the number on the clock like 12 and 1, 7 and 8 etc.