I vary my style. I don't really prefer guided meditations because then it is one more thing I need to rely on.
That said, what works for me is : I have been a gym rat for many years now, I never skip my gym and I am there 6 days a week. I recognized that the only way I can stick to meditation is by including it in my gym routine. So I always do my meditation after working out. Minimum 10 minutes and on good days 20 to 30 minutes. But I never leave the gym without doing it.
I try different meditation on different days. Some days I do simple focus on breathing type meditation, other days I imagine myself circling some random star/planet and focus on it, then sometimes I just imagine waves coming in going out (I try to think of waves as thoughts that pop in and out from my mind), I have also tried chanting meditation - that can be extremely useful in the beginning - I don't do it much though. Finally on days when I have my headphones with me I also try guided meditation (generally I prefer Sam Harris or someone like him who guides through as a non-religious practice).
I really think the key is to try a few styles and experiment with them. I won't trust all the "self-proclaimed experts" who say "this is the only way", just find one that you can relate to and understand the basics of it and come up with your own style - meditation is an art and not a science. I would also recommend that you include it in your routine that you never break (it could be as simple as saying I will meditate before I brush my teeth assuming you brush your teeth everyday :-)). Some days are better others not so much. On some days, the thoughts just keep popping in and out, and other days I feel in a zen mode.
It is incredibly powerful practice, the biggest improvement I noticed is that you become aware of your emotions before they take control of you. For instance, I am short tempered, (and although I am still working on it) these days I notice right before when I am going to loose it and then I think of my "zen state" and suddenly the anger can't take control of me. It is almost like magic.
All the best in your journey :).