Tip: The reason why recording with a good microphone and a well treated room makes a world of difference! Comb filtering bass build up. Some of the culprits to why your vocal sound is not as good as it can be. To solve these problems avoid the following:

1. Using isolation filter/pads. I know they look cool and everyone seems to have them in their home studio... Though they may help with isolation they introduce issues with comb filtering. Busy street that bleeds through? use the polarity pattern in your microphone. And tell everyone in your room to shut up! 

2. Avoid recording in corners. Bass frequencies build up in corners. unless you have bass traps and etc to address this avoid recording in any corner of the room. This includes your ceiling and floor. The best place to record your vocal is in the middle of your room. A well designed vocal booth will have no parallel surfaces and will have the microphone at the center of it. 

3. Spend an extra 5 minutes to record and play back a few takes. Try to get the vocal sound to sit into the instrumental as well as possible. if it needs more depth angle it down towards the chest. needs more "in your faceness" move the mic closer. Harsh sounding high end? angle the top of the diaphragm away from singer a inch. less is more. dont tell them to step back... but to inch back. 

happy music making.