Update practices.rst

fix a typo

docs/topics/practices.rst

@@ -238,7 +238,7 @@ Here are some tips to keep in mind when dealing with these kinds of sites:
 * if possible, use `Google cache`_ to fetch pages, instead of hitting the sites
   directly
 * use a pool of rotating IPs. For example, the free `Tor project`_ or paid
-  services like `ProxyMesh`_. An open source alterantive is `scrapoxy`_, a
+  services like `ProxyMesh`_. An open source alternative is `scrapoxy`_, a
   super proxy that you can attach your own proxies to.
 * use a highly distributed downloader that circumvents bans internally, so you
   can just focus on parsing clean pages. One example of such downloaders is