You should start with your current wardrobe. You may find that you have so much stuff but nothing to wear. This is result of your purposeless purchasing. Now it’s time to make amends. You will have to decide what to keep and what to throw away.
Now, when you know that what is missing from your wardrobe, you should go out for shopping. However, it is better to make list of things you need to create your capsule wardrobe otherwise you will repeat the mistake of buying worthless stuff.
You should buy those outfits that make you feel good, comfortable and confident. Do not go after modern style rather you should be fashionable in your own way. Do not buy something just because the model in advertisement looks good. You have entirely different personality so choose the outfit that goes with your image.
Always prefer quality over quantity and but those outfits that are long-lasting. Do not look at the price tag as cheap clothes won’t work out economical in the long run. If branded stuff is available at competitive price then you should not hesitate to spend extra fortune.
Do not follow the fashion trends blindly as they change every season. Spend wisely by choosing neutral colours and fabric. You may purchase wool, silk, cotton in universal colours like black, grey, camel etc.
Do not feel shy to do experiments with your outfits. Add variety in your wardrobe and it will never be boring.
Accessories are the important part of a capsule wardrobe. Buy some decent silk scarves, cufflinks, belts, bracelets etc.