I noticed a big development in training my pallate when I first started making stocks and sauces. If you are reducing a chicken stock for example, taste it every 15 or 30 minutes and see how the flavour is developing, after a few weeks of doing this you will be amazed at your ability to pick out the sweetness of carrot, fragrace of herbs etc. Smell is also very important, I nearly always smell something before I eat or drink it, it is a bit like an introduction to the tasting, telling your brain what to expect. And always try and keep an open mind, how was your first beer, or glass of wine? Mine was horrible, like most people I was very young and had not acquired the taste yet but perseverance taught me to like them. My wife hates olives and trying them simply is not an option, I am forever telling her that she is missing out on one of the greatest fruits that mother nature has given us and if olives were truly nasty then why do millions of people eat them every day? Finally, stay away from processed foods, always (where practical) buy natural foods, free range etc. You will not taste real chicken from a cheap plastic wrapped rubbery supermarket bird.