Each fruit is different....for the best peaches I look for those which were grown nearest....and smell them.
Watermelon, you thump....the sound of a ripe watermelon can't be described....but has to be taught. Again smell....no hint of mustiness. And the area where the stem was should be slightly soft.
If you buy fruit that was locally grown and buy in season, your chances of finding good fruit are greatly improved.

My best bet is smell; if it smells like like what you think it should smell like - you are on the right track. I have also heard that for melons, if there is a pale spot, that means that the melon was allowed to ripened in the field, which is a good thing. I usually go by the smell with melons.
Jane

If you do a search on youtube on how to pick fruits and vegetables, you will find a ton of "ultimate" tricks. The fact is, I don't know if there is such a thing as "ultimate trick".

Lot's of variables. It depends, for instance:

Pineapple will give a fragrant smell when ripe, but if you don't intend to eat it in a day or two, it may go rotten. Pineapple will get more ripe in room temperature.

Apples will not get more ripe in room temperature.

It is difficult to tell good grapes. Sour grapes will not get sweeter.

Mangos may be green, or yellow, or firm and still ripe, depends on your preference and variety.

People use the sounding method on watermelon, and swear that it works. The fact is, 98 % of the watermelons are good, and chances are whatever methods you use will be effective. The resonance of any object is dependent on the shape, the weight (mass), the static force on it, the temperature at the time ------ just like any musical instrument.

Here is my "ultimate trick" in picking fruits: If I see a fruit that looks pretty good, I will buy a very small quantity, I will take a small taste right after I pay for the fruit, if the fruit tastes good, I go back and buy a lot more.

dcarch

The nectarines available right now have been wonderful, not seen a good peach yet.....could be because of the drought we won't really get any good ones.
think I may make peach jam from nectarines! LOL!

Not sure where in MD you are. Here in Montgomery County there are many farms that sell wonderful peaches right now. Just got three different varieties, but there were too many to choose from. Price is as discussed in other post. White, many types of yellow, new to me yellow skin (never saw this kind before, they look like lemons), all sizes and flavors.

Olga

I bought an Ontario cantaloupe the other day. I couldn't really smell anything, but for 99cents I thought I'd try it.
I didn't get around to eating it for a day or two, then all I could smell was cantaloupe. So it didn't smell in the store, but in a day or two, it was ripe and sweet and delicious.

I can't say the same for the same old tasteless seedless Ontario watermelon. Bleh.

I have had apples that were crisp when I brought them home and turned mealy after sitting on the counter about 2-3 weeks. I bought 2 each of several varieties and let a couple of the seconds hang around a bit too long.

I don't buy a lot of fruit but I know how to buy a cantaloupe, yay, I'm good for something, ha! This is all subjective and I don't claim any great skills so here goes.
Green netting tells me it's not ripe. Yellow netting tells me it could be or likely is ripe IF the blossom end gives when you poke/push it. And after you push that end, smell it deeply. Does it smell ripe and good and tasty for you. Sweet? I picked up two stellar melons, deliciously ripe a couple days ago and they sure were good.

Here's how I am a bad grape picker. I don't care for grapes. So I check out my fellow shoppers and if someone seems to have a special magical bent, I shove my grapes under their noses and ask, would you mind tasting this grape for me? I say, ' Sorry, I cannot eat grapes" and 'would you please give me your opinion. I say that there's a lot of average fruit around and that's ok, too.

I also depend a bit on a local highish end chain and ask their knowledgable pppl to pick out fruit for me --and they come thru.

Corn on cob is a little tricky. They have to be good lookin and if I am really bad, I will taste a kernel. And then, like today, I tossed 4 whole cobs from my frig after about 10 days.

Good stores have good apples for me.

I try to use the sniff test on melons but they are usually so cold they don't have much aroma. My grocery store is freezing in the summer and all the produce is chilly, too. Actually, it's not the best place for buying produce around here -- by far.

I waste a lot of money on not-so-good fruit. One trick I've learned is to check out the sliced watermelon before buying a whole one. If the sliced w-melon looks red and juicy, chances are the whole will be the same.

As for grapes, I like the red ones. If they are pale, they aren't going to be good. Sometimes I use the snitch test for grapes. I try one before buying.

Now that I think about it, there is a lot of tasteless fruit in my store. I was in NY state last fall and bought apples from a roadside stand. They were so good, I felt like I was having an apple for the first time. They even looked more real, not waxy.

The flavor of grapes is very dependant on the variety. I find those little green ones tasteless and sour....I love the big fat pink ones....they are always good....the very dark ones are sometimes good, sometimes not so.
Last year I bought some champagne grapes for jelly....fabulous.....very expensive jelly!

I've been buying all my fruit at the Farmers Market, and all the vendors put out samples. Makes it so much easier.

Well, I do still buy some fruit at Costco - mangoes, South American cherries when they are no longer in season locally (did we have a really short cherry season this year or what?!), stuff like that.

I buy apples, Asian pears, persimmons at the Korean market. They always have good fruit because their clientele insists on it.

The worst store for fruit is Sprouts - they will have one or two specials which are okay, but the rest of the fruit is small and tasteless. Do they think people are fools?

Oops, I'm hijacking the thread now, sorry, too much Earl Grey!

Citrus--heft it in your hand. Toss it up a few inches and catch it. It ought to feel heavy for its size. Thin skinned oranges are often jucier than the thick skinned ones next to them.

Honeydew melon--hold it next to your ear and shake it. If you hear the seeds sloshing around, it is ripe.

Cantaloupe--yellow skin is a good indicator. Be sure there is no mold on the skin or the stem nipple. The stem nipple ought to be curved in, which indicates it was picked when it was ripe. A flat nipple means it was picked green. Test the nipple with your fingernail and sniff to see if it smells like cantaloupe.

Watermelon--I have never been able to hear the thump sound you are supposed to. Be sure the green on the skin is deep green, and the light spot on it is deep yellow.

Bing cherries--firm, shiney skin, deep red.