How can i adjust volume of my tracks with those in the iCloud?
iTunes will not read the tags that MP3Gain uses to set the volume. iTunes stores Sound Check volume information in the iTunNORM tag.

If all of your music is in MP3 format, you could try qNormal.

However, if you've enabled iTunes Match and have a mix of MP3 and AAC files, you could try the commercial product beaTunes. It has a Windows version.

Both applications claim to calculate the appropriate volume using the open source ReplayGain algorithm that MP3Gain also uses.