Personally, I would rake it and do the 'shoe shuffle' at least twice. (A good lawn is all in the preparation). As you will have footprints all over it, give it a very fine rake; just enough to take the prints out. Apply a pre turf fertilizer (available from your local garden centre). It is not essential to water the soil prior to turfing, as you will be watering it a lot after. Buy the best turf you can afford; it makes the difference. Try and buy it from a turf supplier (eg Rolawn), not the local garden centre. The turf needs to be fresh. I used Rolawn as they would cut one day and delivered the next. You must use the turf within 2 days, or it will dry out and/or go mildewy. When you lay the turf, just give it a bang down with the end of your rake (not with a wacker plate like you see on building sites!) and have a plank or 2 handy so that you don't have to walk on the new turf. Watering is essential. You must water (preferably with a sprinkler) for at least 15 mins every day for a fortnight. If you have a sunny garden, wait until the turf is in the shade so you don't scorch it. Hopefully you will end up with a beautiful lawn, but I cannot stress enough, laying the turf is the easy bit; it is all in the preparation. It took us about 3 weekends to do all the prep work and one afternoon to actually lay the turf (about 100 sq. m.). Good luck. It is very satisfying to have all the neighbours ask how you got such a beautiful lawn.