Drills:
You have to have'em- I love 'em. Set aside some time: 10 minutes and build to 30 minutes for your drills 2x's per week at least. You will create more stamina, and increase your strength for better race time. But nothing replacing running a race with running. But these will help ...
Drills to consider perform each for one minute each
run in place
kick your own butt
high knees up put your hands out in front so you have a goal
step overs: from side to side you will sweep right leg over the left for 10 steps then return sweep back across this time left over right to return to the starting spot repeat for one minute.
twist torso Fred Astaire: You will move to the right first for 10 paces twisting your torso and do a step cross step together move then do the same going back to the starting position
skip really high: exaggerate your childhood skipping really bring the knee up and jump as high as you can alternating legs just like a skip.
Straight leg raise Jump: again jumping as high as you can like the skip raise the leg straight in front for 10 paces down and 10 paces alternating legs
fast feet: like football players move those feet in one place as fast as you can
Jump as high as you can
suicides: its the step overs but you will touch the floor at the end and its 5 steps right then quickly 5 steps left
fast ice skating: just like it says: sweep right leg back behind left and touch floor- with right hand--make sure your back stays flat and you look ahead. Not to mention you knee needs to stay right over the ankle; no swaying knee over toe
run in place 2 minutes
kick you own butt for 2 minutes
repeat drills V-calf raises: meaning put your heels together and raise up onto your toes 1minute. rest 10 sec 1 minutes rest 10 sec
If you really want a challenge, now go do fartleks! 
A fartlek is a swedish name for : speed play. Where you put your body to the real test. But do not attempt until you are able to complete the drills with breathe in play.
Have fun,
Core Runner Tracy