The incomparable Michael Barone spells it out for you. As usual, Barone is years ahead of the next analyst. A sample, but you really have to read the whole thing:
Twenty years ago political analysts grasped the implications of the vast movement from Rust Belt to Sun Belt, a tilting of the table on balance toward Republicans; but with California leaning heavily to Democrats, that paradigm seems obsolete. What’s now in store is a shifting of political weight from a small Rust Belt which leans Democratic and from the much larger Coastal Megalopolises, where both secular top earners and immigrant low earners vote heavily Democratic, toward the Interior Megalopolises, where most voters are private-sector religious Republicans but where significant immigrant populations lean to the Democrats. House seats and electoral votes will shift from New York, New Jersey and Illinois to Texas, Florida, Georgia, Arizona and Nevada; within California, House seats will shift from the Democratic coast to the Republican Inland Empire and Central Valley.