Include a large proportion of fresh salads and fruit in your diet. Have a balanced healthy diet.
Expose your skin to sunlight often, and for a significant amount of time, particularly in warmer weather. Understand that after exposing your skin to sunlight, you will smell more than normal. Then after having a shower and washing this off, you will smell less. If you continually eliminate like this, in the long term you will smell less. Swimming in hot weather is ideal, as you expose your skin to sunlight, and wash it as well. People with fair skin should be careful to avoid sunburn.
You can reduce smells by soaking in a bath some time before you plan to go out in public, then having a quick shower before going out. Use non-toxic soap and shampoo.