At a rally in Fort Worth Texas, Clinton made a veiled swipe at Barack Obama, saying she will back up her words with action.
"You give me the vote and the trust that comes with the confidence that represents and I'll give you my best efforts every single day to translate all these speeches into action because there's a big difference between speeches and solutions and rhetoric and reality."
Obama campaigned in Rhode Island, a small state, but one Clinton is expected to win. He told voters his message has stayed consistent regardless of who's ahead.
"Everybody's saying how they stand for change but I want you to understand what real change is. Don't be fooled, real change means saying what you mean and meaning what you say not just during election time but all of the time," says Obama.
Texas, which has the most delegates at stake, is the biggest prize on Tuesday.
Both candidates are running ads there, including some with a distinctive Texan flair.
On the Republican side, John McCain is expected to win handily on Tuesday and possibly amass enough delegates to clinch the Republican nomination.