Comparisons between The Tempest and Twelfth Night?Would be very grateful if I could have some specific scene comparisons?

Well, the most obvious comparison is that both are
"shipwreck" plays.  Both plays begin with a shipwreck, though The Tempest
actually depicts the shipwreck (Act I, Scene i) and Twelfth Night
simply shows the results of the shipwreck, with Viola and the Captain on
shore (Act I, Scene ii).

Both plays involve shipwrecked
family members who go through the whole of the play imagining that their loved ones are
dead (Alsono and Ferdinand assume this about each other in Tempest,
Viola and Sebastian in Twelfth
Night).

Both plays also derive a great deal of
their comic relief from characters who spend a great portion of the play drunk --
Stephano and Trinculo in Tempest (Act II, Scene ii),  Sir Andrew
and  Sir Toby Belch (Act II, Scene iii) in Twelfth Night.  In
contrast, however, these drunk characters are servants (low born) in
Tempest, but high born (Sir Andrew,
Sir Toby) in Twelfth Night.  However, the
relationships between these comic characters are similar.  Both Stephano and Toby are
leaders, know-it-alls.  Both Trinculo and Andrew are followers -- silly and not very
intelligent.

An interesting case for comparison could be
made between Caliban in Tempest and Malvolio in Twelfth
Night.  Both are in service to their lady love, and both are thwarted in that
love.  Both plays end with the fate of each of these comic villains unresolved.  It is
worth noting that, generally, the audience feels a certain sympathy for both characters
which is almost uniformly NOT felt towards them by the other characters on
stage.

Both plays also end with reconciliation in Act
Five.  Those separated by shipwreck are reunited, and marriage is anticipated for the
lovers in each play.