A sunny spot is your first concern, and second is a place with good soil quality. Even if you can fulfil these needs, there are a few other things to consider when choosing the best spot for your plants.
This is a very obvious quality for your field, and likely the first thing you thought of. Your plants will need a full day's sun each day, so you should take a close look at your proposed area at several points in the day. It is easy to miss that a large tree may shade your garden later in the afternoon, if you only look at the area first thing in the morning.
Blueberries prefer acid soil though they can usually do fine even if this isn't perfect. If you can choose a location that already has somewhat naturally acidic soil, it will make your life easier. Otherwise, you will have to do some digging and soil amending on your own.
Test kits can be purchased at most garden stores and are easy to use. To keep it simple, blueberries like the pH to be at least 5 or slightly lower . Further details on soil acidity and other factors are explained on the soil suitability page.
When you locate a good spot for your bushes, don't forget to ensure you have enough space. Depending on the variety, you may need several feet of space for each plant. On average, you should allow 3 to 4 feet between bushes. You can place them closer, but when they grow close enough to touch, this will limit your accessibility between plants when the time comes to go berry picking.
If you grow your plants in rows with the bushes up against each other, then allow at least 4 to 6 feet between the rows so you can still harvest easily.
Standard blueberry bushes will reach 4 to 6 feet in height, which can be a consideration for your planting location if they may end up shading other plants as they grow. It can take between 3 and 4 years before a bush reaches this height.
If you do not have the field space for blueberries, you can actually do quite well growing them in containers instead. Standard plants will be too large but if you can locate some dwarf plants, you should be fine. Tophat is probably the best known dwarf variety, but Northblue and Sunshine Blue are 2 others that you can consider for container growing. A large pot that is at least 12 inches across (or a gallon or so in volume) is fine for each plant. Blueberries have shallow roots so your containers do not necessarily need to be very deep.
Of course, you can also use these smaller plants for in-ground gardening as well if you only have a small area to work with.