Here are a couple resources that will super-charge your Mandarin pronunciation skills.
Pinpin has a nice pinyin chart on their website and an excellent learning tool for mobile devices – free. You can use this chart to explore and compare pronunciation of any two pinyin syllables.
The best feature is their free mobile learning tool available on iOS and Android. With this tool you can easily record your own voice and compare with a model. It is hard to believe that the most effective tool for improving your pronunciation is both free and easy to use. Download this app from iTunes or Google Play.
Yoyochinese also has a very useful pinyin chart. In addition to having very clear pronunciation, this chart provides built in videos with clear explanations of pronunciation. The linked page also contains a number of other resources, including a downloadable pinyin chart.
Both of these resources are amazing in terms of simplicity, usefulness and clarity of pronunciation. Using them together (while studying at Effective Chinese) will accelerate your acquisition of Mandarin.