Here's a great strategy from one of the best personal-development sites, StevePavlina.com. He writes:
"A powerful personal growth tool is the 30-day trial." It's an idea he borrowed from the software industry, where often you can download a trial version of a program for a month before deciding whether you'll pay for the real version.
He explains, "We often psyche ourselves out of getting started by mentally thinking about the change as something permanent--before we've even begun."
The alternative: commit to the new behaviour for only 30 days. That way it's not so daunting and by the end of the month, if it's working, you'll be inclined to continue. If not, you can make some adjustments or try something else.
I'm sure you can see how easy this would be to apply to any writing tasks you may have found too intimidating. Want to write a novel? How about committing to working on it for 30 minutes a day for one month? If that turns out to be too hard to keep up, at the end of the month you can switch to 30 minutes every other day, or whatever you think would work better--and you'll have a month's worth of effort to give you momentum.