Sicilian = sharp+theoretical
Easiest Sicilian = Sveshnikov
Safest Sicilian = Taimanov
Sharpest Sicilian = Najdorf
A move order for Black in the Classical:
6...Be7 no reason to delay this
7...0-0 well, you can delay this move!
8...Nc6 the best squares
Now there is a big split here for Black:
9...Qc7 (idea ...e5)
9...a6 (idea ...b5)
9...Bd7 (idea ...Nxd4, ...Bc6, ...Qd7 and ...b5)
I think the safest and most solid move is 9...Qc7. It holds back White's e4-e5 move and threatens to play ...e5.
Now, ...e5 is often a good idea in the Scheveningen. We have learned that in a lot of Sicilian lines, the d6 pawn is not weak and occupying the d5 square is not much of an achievement. The d6 pawn is difficult to attack and a Knight on d5 can be swapped off, even if it manages to co-ordinate with White's other pieces.
Meanwhile, Black gets a big pawn in the centre, which is supported (unlike White's e-pawn). White's Bishop on d3 or f3 suddenly gets blocked in. Black gets other options, like playing ...e5xf4 and ...Nf6-f7-e5, with a great Knight outpost. So, although this is complicated and you need to be careful, you shouldn't be afraid of playing ...e5. Spassky even showed us that you can play 9...e5 straight away! But I like 9...Qc7 first.
First of all, I think you will get some White players who will think you have made a mistake and play 10.Ndb5. Of course, you will play 10..Qb8, then 11...a6 and after 12.Nd4, the Queen has moved, the a-pawn has moved, but the Knight is back where it was! So, you have gained two moves, thanks to White, and they are good moves to make; your Queen is still thinking about e5 but can also now support ...b5.
Secondly, the most straightforward way to get an advantage
If these positions are a bit too dull for you -- f you think they don't give you enough chances to win with Black -- then you need a slightly riskier line. I recommend 9...a6.