A good rule of thumb in terms of scheduling your time is that you should be spending 2 hours out of class for every one hour in. Thus, with 4 classes amounting to 12 hours a week you should be doing an additional 24 hours of studying, reviewing, working on papers etc, for a total of 36 (roughly a full-time job; you are after all a full-time student).
However, and though it is only scheduled at most 3 hours a week, the Senior Thesis is a 2.0 credit course. Consequently, you should plan on spending 18 hours every week (including class time when we meet). If you do less than this in a particular week then you owe the process more the following week and so on. Schedule this semester accordingly.
The end-product you should be envisioning is the equivalent of a substantial scholarly journal article (which is to be distinguished from both popular magazine articles and website topical discussions).
What makes an article ‘scholarly’ is its specificity, argumentativeness, honesty (in marshalling all relevant information), thoroughness (in drawing and building upon the work of others duly cited), objectivity (in taking seriously strenuous challenges to the dominant thesis), and discursiveness (by addressing scholars in foot/endnotes).
Think about possible topics or themes or events that struck you as interesting in past courses, books you have read, news stories etc and try to articulate why they interest/mystify/frustrate you.
Talk to Professor about it.
Start researching, gathering materials and skimming them.
Begin to keep a complete bibliographical record of everything you skim, scan, and read.
Begin to focus as pointedly as possible on a specific question about what interests you.
This question should be one that emerges from and is a subject of some controversy within the prevailing scholarly debate about the topic or theme.
Devise a speculative answer or working hypothesis (i.e. what do think you will find or end up saying).
You are pursuing a ‘good’ answer (for research purposes) if you know that it flies in the face of at least some scholars who have treated this topic before you.
Specify a plan as to how you will go about answering the question, by testing or attempting to confirm your hypothetical answer.
Get to it.
Plan on communicating with Professor every week, ideally in person but at the very least by email, with newly completed work, and issues or decisions that need to be made.
Be prepared to revise repeatedly all aspects of your work and writing, including answer, question, and even topic.