Aspiring politicians who did not have national acclaim would often attend the convention as a "favorite son". That is, someone nominated by their home state for President, but little support beyond that. Many times, candidates would get themselves nominated as a favorite son, not because they expected to be the party's nominee, but because it gave them delegates that they could use to make deals. It might be getting some cabinet appointment, or even the Vice Presidency. It might be getting some concession from the candidate on an important policy matter, or something that would bring money to the home state. Delegates were currency in these deals. If you showed up to the convention in control of delegates, it made you a player.
This brief history lesson could be relevant this year. No party has had a divided convention, that is one where the nominee did not come in with everyone knowing he would be the nominee, for more than half a century. Pundits talk about the possibility because it keeps things interesting. But the odds of it happening in the current system are highly unlikely, especially in the Republican party where most late primaries are winner take all. The only way a divided convention is possible is if multiple candidates can win first place in a sizable number of States. If Trump continues to win the most States, even if not by a majority, he will win the most delegates and easily take the nomination.
No other candidate has any reasonable chance of winning the nomination outright anymore. The three remaining hopefuls, Cruz, Rubio, and Kasich are hoping to keep Trump from getting a majority by collecting a majority between the three of them. In some ways, each is almost trying to become a "favorite son", although they certainly need to have at least a few more states each beyond their respective home State.
Cruz has already won his home State of Texas, and has a few other wins under his belt, but mostly in conservative closed primaries and caucuses which are not open to independents. Rubio has two small victories, but really must win his winner take all home state of Florida on March 15 to keep going. Similarly, Kasich, with zero first place finishes is hoping to continue collecting some delegates in proportional states to remain relevant, and to win his home State in the winner take all contest on March 15 as well. Trump, of course, hopes to defeat Rubio and Kasich in their home States, which would likely force them to quit the race.
Trump is ahead in both Ohio and Florida right now. Even if Trump loses both contests on March 15, he could still win Illinois, Missouri, and North Carolina on that same day and walk away with the most delegates for the day. Therefore, challengers putting all their chips on their home state seems like a risk, which may still fail even if they win their respective home states. The hope, of course, is that those victories will help them in a few of the subsequent contests and deny Trump the majority.
Even if they succeed in that, and Trump enters the convention with the most delegates but not a majority, there is still the possibility that he can acquire the remaining few he would need to win the nomination. But given the high negatives against Trump, that may be a difficult proposition, even with his legendary deal making skills.
For all the candidates not named Trump, however, any strategy at this point is going to have to be a long shot. The odds remain squarely in Trump's favor.