Personally, I have tried many ways, but the one that works best for my kids are to keep making them try it!
My son is 7 years old and it's a struggle to get him to eat his veggies. Every time we have a vegetable he doesn't like, I give him a couple small pieces, after about 10 times, yes 10 times, he doesn't fight me anymore. If he asks me to melt cheese or add a little butter, I do, whatever will make him eat it!
Now my daughter on the other hand will eat any vegetable out there...
For those of you who have kids like my son, don't give up! Keep making them try it, eventually they'll like them!
As for fruit, if I cut it up and put it on the table, they eat it, don't bother asking if they want it, just do it!