You can, in fact, always meditate, don’t let anyone tell you you can’t.It’s certainly not easy to build up this state, took me a solid 2–3 years, but if you’re sufficiently motivated, you can earn a constant, relaxed, clear state of mind that moves easily and fluidly into trance / jhana if one wishes.
The first step I recommend doing is taking walking meditation seriously. Don’t just meditate on the couch or cushion in lotus pose for hours. This has its place but it reinforces the separation between the meditative frame of mind and the unmeditative. If you want to always have focus, work on that focus in settings you don’t normally consider.
Another thing you need to work on is keeping and being aware of stuff in the back of your mind. When you meditate, you place an object front and center in your mind and you do your best to keep it there. Once you’ve gotten to the point where that’s easy, you need to be able to focus on material matters while not losing your meditative focus. This means, after you’re done with the seated part and need to go back to your life, don’t just forget about it, push it onto the ‘back burner’ of your mind, and revisit it every now and again while you’re in your daily routines.
This is called remembering practice. When you start doing it, you’ll suddenly come to an awareness of just how forgetful mind really is. And the more you fight it, the more painful it gets. Why can’t my mind just work, dammit? Push through the discomfort and just keep trying to put things in the back of your mind and keep them there while doing other things, it’s not a matter of whether you can do it or not, but rather one of acclimating your mind to extra focus and attention duties.
Getting good at this unlocks the next level of working on two focus levels at the same time. For example, if you’re having a conversation with someone, you should be able to use your spiritual vision and processing at the same time that you’re having a normal human-type relating conversation with them. Your mind is used to doing only one at a time. But minds work in parallel, you just need to be able to relax and let the mind open up and see and do everything it wants to see and do in any given moment.
So don’t go getting a big head thinking “meditating all the time” is some kind of big accomplishment. It’s table stakes for a powerfully spiritual lifestyle.