A decent mic will make a world of difference.
Get a decent compressor mic like Rode NT1 etc... very cheap and they sound great.
You also need compression. A slight bit going in so that you get a very hot signal to 'tape'. Then you need to add compression again when you mix it, as well as EQing it so that you get rid of the bottom end.
Other stuff that'll help would be a sonic maximizer to crisp things up.
Then you'd also need a de-esser.
Last but not least, a little reverb or echo