Profile Evaluation (CS Grad Programs)

[Nuiton]

Hi everyone. I am currently a junior majoring in Computer Science (BS) at a university in SoCal. I am considering graduate school, although I am not exactly sure which ones would fit me best. To wrap up my profile, I am going to take the GRE during early summer and plan on retaking it soon after (if I have to, to improve my score). 

Profile:

• Cumulative GPA (3.65/4.0)
• CS GPA (3.95/4.0)
• GRE: Going to take
• Research experience: None so far ?
• Work experience: I'm currently a TA (for Discrete Mathematics, Object-Oriented Programming, Data Structures ...)

I am considering universities such as the following:

• University of California, Riverside
• University of California, Irvine
• University of California, Los Angeles
• University of California, Santa Barbara
• University of California, Santa Cruz
• University of California, San Diego
• University of California, Davis
• University of Washington, Seattle
• University of Toronto, Toronto, CA

If I'd consider a PhD program, what sort of research experience (if any?) would be needed to be considered? I have a few preferences, which would be UCR, UCI, and UCLA. How do I "get" research experience before grad school? I haven't gotten any offers for this summer, sadly.