You could argue that before the story began, the Trojans had already received the help of Poseidon in building their wall, but thanks to their lack of tribute he had withdrawn his protection, so perhaps that could be example number one.

Of course for another you need look no farther than the false dream sent to Agamemnon that suggested he would be able to capture the city in one night if he only raised the army and sent it along to Troy.

A third would be the fact that Aphrodite saves Paris from death and whisks him away to the safety of his bedroom in Troy.

But if you need more, it doesn't take much looking through the story to find them, the gods couldn't keep their hands off of this one!

After a lull in the fighting and exhaustion on both sides leads to a truce, Hera schemes with a group of other gods to break the truce, we can't have this boring peace now can we!

Very soon thereafter, Diomedes comes whipping through the battle rampaging through various groups and killing and wounding a huge number of combatants.  According to the summary:

He even wounds the goddess Aphrodite when she tries to rescue her son Aeneas, and the war god Ares, when he tries to rally the Trojan forces. (Note: “aristeia” is a Greek word which means “excellence” and here refers to an episode in which a particular character demonstrates exceptional valor or merit.)

Later on in the battle Zeus and Poseidon both help the Achaeans protect their ships from the marauding Trojans intent on burning them.

Basically, if you read the story, you can't help but run across gods interfering, without them, the Trojans and the Achaeans would have been drinking together on the beach for a few weeks instead of fighting this incredibly battle.