I'm a fan of GTD, though I don't follow it strictly. My main takeaway is well summarized here: http://gettingthingsdone.com/fivesteps/.

Capture my goals (make running a habit, learn Rust, learn Spanish).

Clarify what that means for each of those things.

Running: MW go for a 5k run @ about 4pm. Done. Now it's in my calendar.

Rust: read the Rust book, create a practice project (which goes into more actions).

Spanish: Get a grammar, a frequency dictionary, a tutor, set aside daily time for reading/review/flashcards.

Organize these, in this case by scheduling time. Sometimes material resources or coordination with others (tutor in the Spanish case), as well. I try to decide whether an activity needs a set time (running) or just any time each day (Spanish w/ Duolingo and Memrise). Look at the calendar and schedule the ones that need a proper time. Daily activities get put in for every day, I can see when I have too many and need to cull my projects, aspirations, or start setting aside dedicated time (Duolingo now actually gets 6-6:30am, basically the 3rd thing I do after waking each day).

Different tools I've found useful: OmniFocus for general organization and project management. Org-mode for delving into details on projects (particularly programming). Notebook and pen for carrying around daily and writing down these things before I forget them.

Get used to working towards your goal daily/weekly. Try to be consistent on the time, schedule it (specific time) if you have to. Otherwise you slip a week, and it becomes two, and then it never happens.