Oh cool, the 2i2 is great (the scarlet series is always winning awards).
In terms of the recording process, it would be really helpful if you have a shock mount (I think the bundle may include one anyway) to avoid any noise from the stand. Also if you can get a pop shield this will help recording quality massively- it'll help with distance from mic and softening any plosives as well as stopping any spit hitting the mic. An obvious thing to do is to find the quietest place possible in your house to record you vocal because the last thing you want is background noise. You also need to be mindful of the acoustic environment- basically if you can avoid a space that is full of reflective services (tiles, laminated flooring and windows/mirrors etc) it would be really helpful. In your situation (and most) you want the vocal to be as "dry" as possible (a clean signal that hasn't been effected by the environment) so recording on a carpeted floor with curtains covering windows will help and duvets are great for absorbing sound reflections. If possible don't have the mic too close to a wall or in a corner, some space between the mic and your environment will be helpful for a better recording just for trying to keep reflections to a minimum.
A good staring point for mic distance is to have the pop shield around 6 inches or so from the mic and then you stand around 2 inches or so from the pop shield but this will need to be adjusted depending on your mic reacts so experiment with that.
If you're singing particularly loud in comparison to the rest of the song a slight move away from the mic will help the overall dynamics and mean you haven't got to be so hard on the compressor when you mix your vocal. It'll also lower the risk of distorting your recording.
Heads up- digital distortion sounds awful so avoid it at all costs. To avoid overloading your interface and creating distorting, try to aim to have your interfaced gained so your vocal signal is reading roughly around halfway in GarageBand on your vocal track. This will be a good safe level which won't distort as you have some headroom and you aren't gained super high so you won't pick up lost of background noise.
Another thing to be mindful of is not having the headphones so loud that you can hear "bleeding through" in your vocal recording. Again, the aim of recording your vocal is to get a really good clear and strong recording because after all, the vocal is the most important part of the track and particularly so in your case when you're recording a cover.
Ok i'll stop there because I can go on for ever otherwise (sorry if the order isn't great, I was just typing as i was thinking). The things I have mentioned are things to be mindful of for the recording process its self but I haven't mentioned the mixing that I assume you'll want to do to make you vocal sound nice and polished afterwards. If you're interested I can go over some general vocal mixing tips and if you have any questions about what i've said then by all means fire away.