The 10K is a great distance for those who have run a lot of 5Ks but aren't quite ready for a half marathon yet. For beginners, the 10K can seem intimidating since it is twice as long as a 5K. However, training for a 10K is similar to training for a 5K.
For a 10K, you need to be able to hold race pace longer, so adding in tempo runs, intervals, fartleks, and increasing your total weekly mileage will help you adjust to the new distance.
10K Training Tool #1: Tempo Runs
Tempo runs are steady-state runs. After warming up for 1 to 3 miles or 15 minutes, whichever you prefer, you run a certain number of miles near goal race pace, then you cool down with an easy 1 to 2 miles. You can do tempo runs for distance or time. A 30- to 40-minute tempo run would include 10 to 15 minutes of an easy warm-up followed by 10 to 20 minutes in the middle at near goal pace, followed by 5 to 10 minutes of an easy cooldown. The pace build-up should be gradual, not a sudden pick-up. You can do the warm-up miles as a progression towards 10K pace.
10K Training Tool #2: Intervals
Intervals are similar to tempo runs but you get a period of recovery after each interval. You alternate fast running with a slow run/jog for recovery, then repeat. The most popular interval for 10K training is 400 meters. You should warm up like you would for a tempo run. The 400-meter intervals should be run faster than 10K pace, closer to 5K pace. Recovery for 400 meters could be running slowly, jogging or walking (if you are a beginner) for 50 to 90 percent of the time it took you to run the interval. The shorter the recovery, the harder the intervals will be.
If you are new to intervals, I recommend having a longer recovery. You could even do a slow run/jog/walk combination of 400 meters following a fast 400 meters. The best venue for 400 repeats is on a track, but they can also be done on the roads and greenways. You want a relatively flat surface without traffic lights, stop signs and anything else that would force you to stop an interval to cross a road or path.