Hillary Clinton enters the general election with considerable advantages over Donald J. Trump: She has a stronger and better-funded organization, and the electoral map is tilted in her favor. President Obama’s endorsement on Thursday accelerated the process of rallying Democrats around her candidacy.

Mrs. Clinton now has a chance to exploit that edge, while Mr. Trump struggles to bring together the Republican Party and build an effective campaign organization.

A look at some important things Mrs. Clinton could do to press her advantage in the coming weeks:

Head off Trump in the Midwest

It is no accident that Mrs. Clinton’s first campaign swing of the general election will take her next week to Ohio and Pennsylvania, and that her first joint rally with Mr. Obama will be in Wisconsin. Mr. Trump has long vowed to compete in traditionally Democratic-leaning Midwestern states, viewing the Rust Belt as the cornerstone of his electoral map.

Given Mr. Trump’s dismal standing with Latino voters, his prospects look tenuous in traditional swing states like Colorado, Florida and Nevada. That means his most realistic path to victory runs not only through Ohio, a perennial battleground, but also through states like Michigan and Pennsylvania that have not voted Republican in a generation. If Mrs. Clinton can fortify her support in these areas, Mr. Trump’s electoral map may disintegrate.