The best thing you can do is control temp at the recommended level from either the yeast package itself or the recipe.
For most ales, that's in the 60s. As
@Jtvann notes above, fermenting at 70 could get you temps as high as 80, which will not be what you want.
There are lots of ways to keep ferm temps down.
@histo320 notes the swamp cooler, which is the cheapest way to do it. Some may put frozen water bottles in the water of the swamp cooler to help it, if the ambient is fairly high. Below is a pic of a swamp cooler.
The preferred (and more expensive) way is to use a freezer or refrigerator to control temp, using a controller to monitor temp and kicking on the unit when it needs to keep temps down. I've included a few pics below showing my two ferm chambers, one a larger refrigerator I bought for a song, the other a tall dorm-style refrigerator for which I paid $60. Both are controlled by
Inkbird 308s, which are excellent yet inexpensive controllers (I have five of them).
You can even go uber-pricey by buying a glycol chiller and using a tubing system to control temps. For most home brewers, though, the refrigerator/freezer approach is more than enough.