OK for nice vocals the preamp is the way to go.

You can pick up a Behringer Ultravoice Pro second hand for about 60 bucks. It will dramatically improve your sound and contains things like a de-esser, tunable voice optimized EQ a tunable Low cut filter as well as the option to add warmth (via tube emulation). Be warned that Behringer has a rep for producing knock offs and for bad quality control. I used an Ultravoice pro for a while and thought is was OK. It worked every time I turned it on so I cant complain. I also have experience with ARTs tube preamp system (V3TPS). This is OK, more expensive and more versatile than the Behringer but not so good for vocals (IMHO). Im using a Focusrite Platinum Voice master Pro at the moment and it is orgasmic.

Tips.
1) use a Pop filter with a condenser to reduce plosives
2) aim the mic at your nose
3) Place a Gobo (like a towel on a mic stand) after the mic but between you and any big reflective surfaces.
4) don’t be afraid to do 3 or 4 takes at one go and make a montage of the best bits of all your recordings. You will have the most success with this approach if you can keep your levels the same between takes
5) mark a spot on the floor where you put your feet and this will help maintain constant levels between takes
6) Use a lot of compression !
7) be aware of the proximity affect. If you get too close to the mic, roll off some bottom end.
8) add reverb / delay in the mix, don’t record it or you are stuck with il forever !
9) check your performance through monitors and not just headphones.
10) put your thumb on your chin and stretch your hand away from you. you should only just be able to touch the mic with your pinky, otherwise you are too near (i.e. into proximity effect land)
11) There are no rules, if it sounds good, you have got it !

Best of luck
S