Step 1: Make Reasonable Goals for Yourself
After several years of not writing much at all -
Goal: Write something every day! is a goal many of us make for ourselves.
While this is a good goal for someone who has been writing for a long time - think about it in the terms of someone who has gotten out of the habit. Miss it once even when attempting to get back into the habit of writing, and you've already missed that goal. It's not a very encouraging situation, there.
A more reasonable approach would be a gradual increase in the goals until you reach that final goal.
Goal #1 - Write once a week for 8 weeks.
Goal #2 - Write twice a week for 8 weeks.
Goal #3 - Write four times a week for 8 weeks.
Goal #4 - Write five or six times a week!
It is a gradual increase, gets you back into the habit more gently, and still has the same final goal of writing most every day. Yes, my proposition takes about six months, but let's be honest... creating a habit takes time. It's not something done overnight. Just like everything else, you have to train yourself to do it. Give yourself some baby steps, and gradually make them bigger. If you move faster - GOOD! As long as you are reaching your current goals. You'll be writing in no time!
Notice something, please. In the final goal, I do not say, "Write every day!" If you do write every day, that's awesome, but it is good to build in days when you might not feel well, or when you did not sleep well that night, or maybe you just want to take a day off or spend some time with the kids, family, or friends.
If you go two weeks in a row without meeting the particular goal you are on - start it over again. Again, this is creating a habit, so it will need to be practiced.
Step 2: Document Your Progress
Get a little notebook to keep near where ever you write, or have a little online blog - something where you can keep track of your progress. Then, update it every... whatever time slot you have your goals set for. In my example above, it would be updated each week.
It doesn't even have to be much. It can be, "I made my goals this week! I felt that what I wrote on Tuesday was a little short, but I did get the writing done." Or, "I didn't make my goal this week. I don't know what happened! Things just got so hectic, it simply didn't happen. I'll try to do better next week."
Step 3: READ!
It is important, uplifting, and worth the knowledge to pick up other books and read them. Not just the modern popular books, though that is good information on what people are currently interested in, but classics. Read some of the older literature that turned reading and writing into what it is today. Read some of your favorites just to remind you what made them awesome. Read a new author, just to try them out. Read a genre you've never touched before, just to get the experience of having done so. Read, read, read!
You might even want to make a reading goal, just like you'd make a writing one, if you are not already an avid reader.
Reading is just as important as the writing simply because - hey, these people have been successful! These people have accomplished getting published, have caught the attention of readers, and can teach you a lot about what it is you need to do if your final goal is being published, or making writing your job.