My general advice to any beginning producer would be to mess around with some good sample-packs first, and then once you get the hang of structuring your tracks the way you want, dump the sample packs and get to shaping your own sounds. That's when the real magic hopefully starts to happen. Doing it the other way around is noble... but you'll spend ages trying to get your sounds fat or a certain way or whatever. That's how I got started.. it's helped my sampling and sound design a LOT (i can turn anything into anything) but mostly it's been a waste of time..
Then again, UK garage is so broad.. a lot of what I enjoy about is stuff that almost revolves around breaking musical rules.. out of key, out of time, just clever ways of getting sound.
You gotta keep in mind what kind of sound you're after and how the people that came up with it made it originally. If you're looking for a raw, underground sound... then use raw, underground tactics. Use dirty sounds, use that crappy old synth people forgot about... work with tape recorders exclusively... do something crazy. You see a lot of producers producing so neatly within the lines nowadays.... which is why a lot of it sounds great, but utterly the same.. you can do that perfect, break, build, drop thing all you want, but it'll always be boring and safe.
To me 'garage' (in whatever form: house, UK, deep, bla, future, grime) is supposed to be the giant middle finger up the ass of all the neat glossy genres and established production methods.
Also one of the best general tips I ever had: stop listening to the music you're trying to make! It'll just get in the way of your own creativity..