The problem, I think, is that you know that you must do a lot of small tasks, but you don't know which exactly. So the tasks become an enigmatic mass of entangled problems, which weighs upon you and leads to anxiety, which leads to procrastination.
The goal is, then, to take stock of your tasks and structure them.
You've almost finished developing a website, but there are a few problems that you must taclke.
Firstly, let's list them:
- Complete cross-browser compatibility for IE8.
- Check for inconsistencies between your web page and mock-ups.
- Fix a small bug in the server-side form validation script.
- Decide upon an animation effect for a dropdown effect.
This feels better, because it's actually not too much. But there's still anxiety left, because you don't know how exactly you will tackle these tasks. So let's divide them into as many meaningful substeps as possible.
Complete cross-browser compatibility for IE8.
1.1. Check the website in IE8 and compare it to the browser of your choosing.
1.2. Find and list the inconsistencies. (you can list them right here later!)
1.3. Remove the inconsistencies.
1.4. For inconcsistencies that couldn't be removed, plan graceful degradation.
1.5. Discuss with the designer about your plan for graceful degradation.
1.6. Implement graceful degradation.
Check for inconsistencies between your web page and mock-ups.
2.1. Check for inconsistencies each webpage of your site (list the pages here)
2.2. Fix the inconsistencies. (list the inconsistencies here)
Fix a small bug in the server-side form validation script.
3.1. Find the cause of the bug.
3.2. Fix it.
3.3. Run unit tests.
Decide upon an animation effect for a dropdown effect.
4.1. Propose a solution or contact a designer for a solution.
4.2. Implement the solution.
4.3. Run unit tests if applicable.
4.4. Check for crossbrowser compatibility.
4.5. Implement graceful degradation if neccessary.
Now you have a full picture of what you must do, and there is much less anxiety about the upcoming work. There will be no surprises along the way (or at least not as many as there would've been). Now you can focus on tackling the tasks and forget about everything else.
As you go on about completing them, you remove them from this list.
Workflowy is a really useful tool for this, because it's basically a list creation application, so moving list items around, striking them out or changing the hierarchy is really simple.