Variety selection is key -- especially if you live at more northern latitudes, which have shorter growing seasons. Find out when your first date of frost is anticipated in the area you want to grow in. It's also important to note if heavy rains are a factor in your area. For example, in parts of the Pacific Northwest, bud rot from cold wet rains are more likely than the first frost to wipe your crop out if it doesn't finish in time.
Once you determine when the season comes to a close, you can make a better decision on how early you need your plants to finish when selecting seeds or clones. 
Auto-flowering strains can be grown from seed, and regardless of day length go into budding after they gain a few sets of leaves. This is an option in tougher climates, or for those looking to harvest earlier or more than once per outdoor season.
Clones that are proven to perform in your area have an advantage. because you know it's a good bet you'll be able to harvest before the end of the season and what you can expect to yield for your efforts. F1 Hybrids from regular seed are bred for outdoor growing conditions.
Seed plants are free of insects and diseases -- it’s literally a fresh start. Further, when cannabis grows from seed, it develops a tap root, while from clone it's fibrous roots only. A tap root can anchor the plant down and drive it deep into the ground in search of water and nutrients. The disadvantage of course, being that you don't know whether it's a male or female from regular seeds.
However, you may sex plants with a high degree of certainty by the time they are ready to transplant outdoors with a little bit of practice.
Start cannabis seeds under 24 hours of fluorescent lighting at or right after they germinate (sprout from seed). As the plants develop, start decreasing the light cycle by a couple of hours every day until lights are 16 hours ON and eight hours OFF.
Young pot plants that have four or more sets of leaves, will often show some pre-flowers in about one to two weeks without going into full-on flowering, as the critical 12/12 day length has not been reached. The most visible pre-flowers appear a node or two down from the tip, right where the leaf stem meets the main stock on the young plant. There are lots of great guides out there that make spotting the important difference between male and female plants easier.
Harden transplants off before final planting. Gradually expose them to outdoor light levels and cooler night temperatures, for example, for an hour or two at a time, while increasing the exposure over a couple of days. Hardening off helps reduce shock and makes the crop more resilient to whatever life has in store for your plans.