Page Speed Issue

One of the major reason for slower website speed is “Leverage browser caching”. I really have no idea what to do about it
Can someone please help me with this…. Below is the message i got from gtmetrix.com website

Leverage browser caching
The following cacheable resources have a short freshness lifetime. Specify an expiration at least one week in the future for the following resources:

http://www.ilampion.com/wp-content/cache/minify/000000/M9bPKixNLarUMYYydHMz04sSS1L1cjPzAA.js (expiration not specified)
http://www.ilampion.com/wp-content/plugins/aeroleads-contact-us-details/admin/md-font/css/material-design-iconic-font.min.css (expiration not specified)
http://www.ilampion.com/wp-content/plugins/aeroleads-contact-us-details/public/css/flat-sh.css (expiration not specified)
http://www.ilampion.com/wp-content/plugins/aeroleads-contact-us-details/public/css/fonts-sh.css (expiration not specified)
http://www.ilampion.com/wp-content/plugins/aeroleads-contact-us-details/public/css/simple-sh.css (expiration not specified)
http://www.ilampion.com/wp-content/plugins/aeroleads-contact-us-details/widget/md-font/css/material-design-iconic-font.min.css (expiration not specified)
http://www.ilampion.com/wp-content/themes/sydney/images/2.jpg (expiration not specified)
http://www.ilampion.com/wp-content/themes/sydney/images/header.jpg (expiration not specified)
http://www.ilampion.com/wp-content/uploads/2016/03/certificate-champ-transparent.png (expiration not specified)
http://www.ilampion.com/wp-content/uploads/2016/05/adsense.jpg (expiration not specified)
http://www.ilampion.com/wp-content/uploads/2016/05/affiliate.jpg (expiration not specified)
http://www.ilampion.com/wp-content/uploads/2016/05/email.jpg (expiration not specified)
http://www.ilampion.com/wp-content/uploads/2016/05/iLampion-logo-small.png (expiration not specified)
http://www.ilampion.com/wp-content/uploads/2016/05/orm.jpg (expiration not specified)
http://www.ilampion.com/wp-content/uploads/2016/05/sem.jpg (expiration not specified)
http://www.ilampion.com/wp-content/uploads/2016/05/seo.jpg (expiration not specified)
http://www.ilampion.com/wp-content/uploads/2016/05/smm.jpg (expiration not specified)
http://www.ilampion.com/wp-content/uploads/2016/05/trail-four.jpg (expiration not specified)
http://www.ilampion.com/wp-content/uploads/2016/05/website.jpg (expiration not specified)