Hey,
Some stuff to consider:
1. Walk before you run. It's going to be REALLY tempting to try to sound like Eric B., but remember that you're not using turntables and he's been doing it for a very long time. Maybe try to learn how to match beats, get two discs to playback in sync.
2. Most, if not all, hip hop music is written in 4/4. This means that in every measure there are 4 beats...if you listen to a record, you will be able to count '1...2...3...4...2...2...3...4...3...2...3...4...4...2...3...4...' After a while this counting will come naturally, you'll be tapping your feet in time to everything.
3. If your scratches don't sound just like what you hear on albums, it may be because cd turntables don't sound like vinyl turntables...but there are some really cool things you can do with the cd decks that you can't do with vinyl!
Take care,
Nick