In the real world light creates colour, but in painting colour creates light.
A few tips on how to use colour in your painting.
Some colours are considered warm - red, yellow, orange, some are cool - blue, green. Think fire and water. These colours can contrast well, and if handled correctly can result in a wonderfully colourful piece of art - think Van Gogh's yellow sunflowers against a vivid blue sky. But caution is needed and the artist needs to understand when and how to use these contrasting colours.
Often beginners use too much colour - remember, for a more elegant painting be conservative in its use and limit your palette. Often less is more when it comes to colour. Using every colour in your paint box collection will not give the best results.
Value is more important than the colour itself. Value is light and dark of the same colour - understanding value will result in a more professional look than using a lot of different colours. Mix various values of the same colour on your palette before applying paint to the canvas.
Tone is greyed down colour. It might sound a bit dull, but toning down a colour can make colours look more natural. Too many bright colours can look chaotic and be hard on the eye.
If you are going for a splash of colour, maybe to create a focal point, use a palette knife of a few brush strokes to avoid losing the vibrance. To really make a vibrant splash of colour stand out, put it against a neutral background.
To understand value better, take a photo and look at it in black and white. Taking time to master colour, value and tone will result in a much better painting experience.
Happy painting and do let me know how you are getting on with your latest work.