user19941: In Bughouse, players often target the f2/f7 square; it is common to see a minor sack on f7, followed by a knight on g5 delivering check and breaching through the opponent's defenses.
I recently played a Lichess Bughouse game where, even though the opponent castled, the f7 square still offered opportunity.
Personally I think I'm still novice with bughouse, so I'm wondering if just attacking the f2/f7 square is a good rule of thumb. Or, is there is some better general advice for beginner or intermediate players to follow?

user12873: In general it's a good idea, but to every rule there are exceptions. For example, if your opponent's king is safe (such as from castling) and he has lots of pieces around defending, sacrificing the knight on f7 may not be a good idea.

user9684: https://www.youtube.com/channel/UCcKXwA_lo3Zpz3_Mc-WVLtw is the YouTube channel of Helmsknight.  She is a strong player who plays with Nakamura, Seirawan, and many other high rated players.  Interesting is that all these players tend to castle before starting an attack.
Just like normal chess, starting an attack on this (these) square(s) is often a good idea.  However, I used to take advantage of this common attack and have both boards play passively.  Soon my opponents would be down a couple of pieces (on each board sometimes) and no resources to continue the attack.
For a better understanding of proper use of resources, Crazyhouse is the variant.  

19941: <p>In Bughouse, players often target the f2/f7 square; it is common to see a minor sack on f7, followed by a knight on g5 delivering check and breaching through the opponent's defenses.</p>

<p>I recently played a <a href="https://www.chess.com/live#g=3976463097" rel="nofollow noreferrer">Lichess Bughouse game</a> where, even though the opponent castled, the f7 square still offered opportunity.</p>

<p>Personally I think I'm still novice with bughouse, so I'm wondering if just attacking the f2/f7 square is a good rule of thumb. Or, is there is some better general advice for beginner or intermediate players to follow?</p>
 12873: <p>In general it's a good idea, but to every rule there are exceptions. For example, if your opponent's king is safe (such as from castling) and he has lots of pieces around defending, sacrificing the knight on f7 may not be a good idea.</p>
 9684: <p><a href="https://www.youtube.com/channel/UCcKXwA_lo3Zpz3_Mc-WVLtw" rel="nofollow noreferrer">https://www.youtube.com/channel/UCcKXwA_lo3Zpz3_Mc-WVLtw</a> is the YouTube channel of Helmsknight.  She is a strong player who plays with Nakamura, Seirawan, and many other high rated players.  Interesting is that all these players tend to castle before starting an attack.</p>

<p>Just like normal chess, starting an attack on this (these) square(s) is often a good idea.  However, I used to take advantage of this common attack and have both boards play passively.  Soon my opponents would be down a couple of pieces (on each board sometimes) and no resources to continue the attack.</p>

<p>For a better understanding of proper use of resources, Crazyhouse is the variant.  </p>
