I believe it's really important to establish a routine as a writer. You can't just write when you feel like it and gain any type of success.
For me, I wake up around 6:15, eat, dress, watch TV news and get to my desk by 7:30 on most days. I start by turning on the computer, checking emails and catching up with the news on various websites. If I'm on schedule to send gags to someone that I've already put together in a batch, I send them off right away so that I know it's done. Then I read my local newspaper, Newsday, (I still read newspapers) plus the New York Times. I get plenty of ideas by reading news and features. As I'm reading I'm writing down words, phrases and ideas that I will use in my gag writing. After I've written down lots of ideas and random words and phrases, I begin writing gags and then I type up what I've written.
If I'm writing business gags that day, I might read the Wall Street Journal online. Sometimes I take out books from the library (yes, I use the library!) about business trends and get ideas this way. I also look at published business gags online to get the creative juices flowing. If I'm trying to write gags about cooking, for example, I might read cookbooks (also checked out from a library) to pick up phrases that I can use in my writing.
I'm a big watcher of TV news. I watch local and national news programs, sometimes just to get the headlines, at breakfast, lunch, just before dinner, after dinner, and if I can stay up that late, just before bed.
I write for about five cartoonists right now. I have a regular schedule as to whom I'm writing for on any given day, who I'm compiling gags for, and who I'm sending gags to, either by snail mail or email.
Oh, and did I mention that I write to-do lists for each day and cross off items as they're completed?
Did I also mention that I check my mailbox multiple times a day to see if the mail arrived, hopefully with a check inside? I usually stop "working" for the day, at my desk, at about 4:30 or 5pm., at which point I can't think straight.
This regular routine is really important to me. There is a structure to what I do and I think this is really important to being productive.
Finally, a writer is constantly formulating ideas. The habit of doing that doesn't stop at 5pm or on the weekends. You have to observe people, the world around you, and, for me, look at myself as a great source of humor. I also have to remember to write things down.