Ways to check your IVs.
The easiest way is by having a friend to do a level 100 Wi-Fi battle with you. Record your Pokémon’s level 100 stats and plug them into the IV Calculator of your choice. The 2nd and most effective way is to own 2 DS and just battle yourself
Step 3: How to get a rough idea of your Pokémon’s best IV.
You can get a rough idea of your Pokémon’s characteristic. Characteristics are a new stat added with Diamond/Pearl. The phrase you can see on the Pokémon’s stat card is the highest IV your Pokémon has. Also if you have more then one stat tied with the same IV number this phrase will be randomly picked. Instead of typing out every IV and its phrase, here is a chart.
Example:Lets say you want to have a starly caught in the wild to be iv in speed then when u catch the pokemon u check at its description and if it says 1 of the descriptions in the speed catagory then that means it is stronger in speed depending on what stat u want it based on