The way I managed things is I gave everything to someone else:)

I just remember things.

No need to write long lists or fiddle around with software.

Like this, just without the white tie.

http://www.transitionministriesgroup.com/wp-content/uploads/2013/07/juggling-chainsaws-youtube-i4.jpg

i do not remember things, as a general rule.  i have found that when i do remember things, i get in trouble

i have evernote on a tablet.  also syncs to clouds and desktops and such.

Wing it.

If I forget it, it wasn't important.

hang them all on a tack board, when i come in the morning i throw a dart and which ever one the dart hits that's the one that gets ignored for the day

if its not important it ends up on a post-it note. if it is important i am thinking about it and that could be up to 5 projects cycling through. so lets say i have 15 projects that day on the burner , 5 i care about, 5 i write down to get to, and 5 i try and avoid but they usually involve pesky clients who call and email all day.

Know your target delivery dates (What? When?).

Backtrack and set interim progress milestones from that.

Figure out what needs to happen to meet those milestones.

Use that as your task list (write it down if your memory is unreliable or it's more than seven tasks).

Prioritize the tasks (PROTIP: do not skip this step).

Start working you way through the list in order of priority (highest first, lowest last).

Periodically check to be sure you're on track.

Thanks for all the responses chaps, I have to say the chainsaw juggling did raise a smile!

Thanks sharmanandini and gwharton for your insight.

Would I be correct in assuming that most architects simply use their memory and pen/paper to jot down notes to keep themselves organised? With the exception of a few who seem to have a system or some software to help them out?

Does anyone use ArchiOffice? I have done some googling and that seems to target architects in particular. 

Far more important than any tool you use (software, etc.) is a set of good habits. Developing those habits is not tool-dependent. You can do it just as easily with pen-and-paper or even tying pieces of string on your fingers as you can with a gold-plated CMS. Don't worry about software until you've established habits which require more sophisticated tools to streamline them.