Mastering volume??

Hope some knowledgeable guys can help me here. I am no where near being a mastering engineer but I'm practising hard at it :) one of the things I'm struggling with is getting the volume as loud as commercial mixes it's just no where near. Yesterday I mixed a bands record which I think sounds quite good, and as the band has quite a tight budget they have asked me to master it for them. I my chain I had

Waves 2500

Epure EQ

Waves L2 to limit 1db of peaks

Waves vitamin

Slate FX-G



Now on the slate the RMS was reading around -10 and -9.5 which I thought was what is a good red to aim for but up against commercial releases its just to quiet. I'm hoping some people can help with tips or advice which I could try or areas that I maybe going wrong



Thanks in advance