I customized a wordpress theme which is nearly finished. Yesterday I check my page speed through google and other websites the page speed is about 80%- 85% which is okay for me. But google provide me few suggestions such as Leverage browser caching, Minify CSS, Enable gzip compression, Avoid CSS @import, Specify a cache validator, Optimize images, Minify JS and many more suggestion. One more thing is that whenever I load my website everything load but the white backgroud come after that which doesn't look very good if someone please help me with this will highly appreacite.

Thank you!