If you decide to feed your lizard with the pre made dry pellets, it's worth moistening them prior to feed time, this will make the more palatable to your lizard. It's a smart move however, not to religiously cling to manufactured foods, a lizard although will survive ok on this, it's more desirable to use a range of food, some dried some fresh. A great way to add fiber to your lizards diet would be to feed them regularly with sprouting pulses, you can often grow examples of these at home, mung beans and the like can be cheaply produced at home even without a garden.
Lizards will often enjoy a selection of more commonly found vegetables such as cabbage and carrott; you may also try a little red lettuce. Some lizards will happily feed on certain fruits, apples, melon and grapes are popular and easy to obtain, but you should be sure to avoid rhubarb as its toxic to many lizards.
It's important to consider food preparation, whilst larger pets may be able to eat and chew down larger leaves and chunks of vegetable and fruits, smaller lizards will require some preparation. Its important to ensure vegetables such as carrots are chopped down to small sizes suitable for swallowing, you will need to gauge the size required by the size of your lizard. Lizards can get a little excited at feeding time so ensure their food is in a solid bowl that won't easily tip over.
You may wish to consider some supplements for your lizard's food, check with your pet store for more detailed advice, but you can buy a range of sprinkle on vitamins and mineral supplements, these will aid the ongoing health of your pet lizard.