What model of camcorder is your video coming from?
Which version of the program are you using on what operating system?
When you add your first AVCHD clip to your Premiere Elements projects, is there a yellow orange "render" line above it? This is an indication that the projects settings have not been properly matched to your video specs.
Other that what Steve has suggested, you can check the Edit>Preferences>General and then change the render quality to High Quality from Draft quality. Also, you can right-click on monitor and change the playback quality to Highest. Please share your observations after making these changes.