Wild strawberries are very tasty, but I have only ever found them by accident.
What locations would be good starting points to look for them?
I enjoy going out every year and picking wild fruits out here in Beautiful British Columbia.
Many times a year, I will go out picking berries, early in the morning with a friend if possible. My favorite place to go berry picking is down near the Fraser River. I tend to make it a multitask day, by picking other berries at the same time and have even done fishing or gold panning where I go on the same day.
It is not worth your while to go out wild strawberry picking as James Jenkins' answer points out. When I do it, I take along several small containers in order to pick several different types of berries at the same time: salmonberries, blackberries, dewberries, wild raspberries and so on. I usually will do this several weekends in a row and put the berries in separate containers in my freezer until I have enough to make something out of them. If not I can make a mixed wild berry pie or wine.
Where to find wild strawberries?
Wild Strawberries grow in many habitats. When they are found in old orchards or under Wild Black Cherry (Prunus serotina) trees, Grape Ferns (Botrychium spp.) often grow with them. Wild Strawberries tend to be semi-evergreen. Sometimes they still possess last year’s leaves when the plants flower in the spring.
Get out and look for strawberries along the edges of abandoned farm fields. - Michigan’s Wild Strawberries
This source gives a little more information:
Beach strawberries (Fragaria chiloensis) can be found along the upper edges of beaches on Washington and Oregon coasts. The leaves are thick and leathery compared to those of other wild strawberries of the Pacific Northwest.
The other two strawberries in the region are usually found from the interior valleys west of the Cascades to alpine areas throughout the region. Wild, or Blue-leaved strawberry (Fragaria virginiana) and Wood strawberry (Fragaria vesca) are very similar in their leaves, flowers and fruit. They are found growing along the edges of clearing in woods, and often on rocky, warm south-facing slopes. The bright red fruit of our wild strawberries is quite delicious and very similar in appearance to domestic strawberries except for size, but the flavors of the native strawberries are quite different and special. The berries are found in greatest quantities May-June, depending on location. - Three Wild Strawberries of the Pacific Northwest
The location I go to has salmonberries and blackberries in abundance at shoulder height and wild strawberries at ground level and in front of the berry thickets. It is a gold mine for berries.
The only downfall is that there are sometimes bears around. They like berries too.
I have picked wild strawberries in Colorado often while I am out hunting. My go-to place for wild strawberries is on old logging roads that have been overgrown. It takes some clear area with shade, but a little sun during the day. By hiking up old logging roads that twist and turn, you can often find them either in the road or on the side of a cut where the shade/sun mixture is just right. If the logging road is starting to have little sprouts of trees coming up, but isn't completely overgrown, you are probably on a good candidate road. Moisture is another factor, but it is easier to look for strawberries than moisture.
Another place to look is in rock slides where there are marmots. I think the marmots are out eating the berries and the seeds end up in the rock slides when the marmots return to home. I have often found them with the marmots or near the marmot homes. Wild raspberries seem to do a little better where the marmots are, so don't pass those up while you are searching for the berries. Sometimes the rock slides the marmots prefer just have too much sun for the berries, I think.
Seeing wild strawberries isn't easy. You have to really be looking for the plant shape as often the berries are hiding under leaves, so make sure you have that picture in your head as you hike.
Since geographical area was not mentioned, Smultron are very common in Sweden.
I am not sure about the botanical definition of wild strawberries, but usually Smultron is translated as wild strawberries and Jordgubber are strawberries
They are common all over Sweden, personally I have found them in a lot of the less populated areas in and around Stockholm, which due to Stockholm's lower population density is something very common, and especially in the Roslagen area to the north of the city.
It's common for young adults and kids to string Smultrons on a piece of grass.
In the bellies of critters...
Seriously, anything living in the area is going to know where the wild strawberries grow and will have made a habit of eating them when they get ripe.
They grow close to the ground, so unlike black berries and other high bush berries, every critter can easily get to them birds, mice, etc. I used to frequent a grassy area with wild strawberries, and I probably saw 200+ green ones for every red one.
It will only be by luck that you will get to them before the local wildlife.
Disclaimer: I have no expertise in botany; what follows is just my own anecdotal evidence. But I usually manage pretty well to find them.
They seem to be most common in half-shaded areas - not in deep shade (almost impossible), not in bright sunlight (possible but less likely), but somewhere in between. Look for areas that are relatively sheltered from the sun, but still have lush, thick, green vegetation at the knee-to-waist-high level.
I have the vague impression that wild strawberries tend to more common next to conifers than next to deciduous trees, but I am not quite sure about this (maybe this is just my own stereotypes).