Different things work for different people. Some people are simply built to land more on their heels. I had a very good (Ivy League champion) sprinter who ran on her heels! It's perfectly possible to land *lightly* on the heel, then have most of your weight landing on the midfoot or forefoot.
BUT--if you're landing *hard* on your heels, there may be a problem. Think: if you were running barefoot (not that I'm necessarily advocating that), would you really land hard on your heels? Ouch!
The "cure" for this--not necessarily moving off the heels completely, but landing lightly on them instead of heavily--can come from two things: strength work for the legs and abdominal conditioning.
1) A lot of heel-strikers tend to land with an almost-straight leg, which contacts the ground noticeably in *front* of their center of gravity. Regardless of heel striking, you want to avoid this in-front-of-CofG landing because it's a braking force--slows you down. (Everything that moves you forward happens under/behind your CofG.)
You want the foot to land more nearly under the CofG--that'll slow you down less (and also tend to move you off the heel some). But to do that, you have to land with your knee a bit more bent; and to do *that* you have to have some quad strength. Leg press and squats help here; so do short sprints (5-10secs) up a kinda-steep hill.
2) If your pelvis is level--rather than tilted forward--you'll tend to "lead with the knee" when you take each step, rather than leading with your foot. I'm not saying that you should run distance with *high* knees!--but your knee and not your foot should be what you feel like you're taking steps with. Again, leading with the knee means your foot is less likely to land well in front of your CofG--the foot will land more nearly under the CofG (and ideally will be moving backward as it does).
Abdominal strength makes it easier to maintain that level pelvis. You can find plenty of advice about abs exercises online (try YouTube), but ideally you want to build up *gradually* to more intense exercises (things like basket hangs, etc.), rather than doing hundreds of low-intensity reps. If you can do more than 20-30 reps in a set of abdominal work, it's probably too easy for what you want--add resistance or move to a more challenging variant.