Firstly, apologies to Nick for misrepresenting the process of him getting to 1st path! The Hamilton Project blog is an excellent resource by the way and I'd recommend checking it out 'cause it's full of really good information and real-life experience from three accomplished meditators.
I'm not sure what you mean by concentration here. Me and concentration have a funny relationship, oftentimes involving headaches and other not so fun things. It really helped me for a while to do metta meditation with Bhante V who taught a practice that didn't separate concentration/tranquility from insight. And also Adya's let-go-of-control approach. I find now that when I try to do just plain concentration practices, they may initially calm my mind and create some nice states but if I do them long enough or after a few uses of them I start to get the excess tension/headache thing and have to let them go. So I have to be really careful how I practice. Now I'm wondering, are the jhanas the same in both these approaches (concentration practice separate or not)? Would help to make sure I'm using the right vocabulary.
If I say "concentration", I'm referring to samatha i.e. tranquility i.e. nice, stable and relaxing
states. I think there's a few traditions which don't separate concentration from insight, my own practice is very much like this most of the time actually, but I would generally make a distinction between the two when talking to people about practice. I really like Adya's approach and I think Jacob may be pointing to something similar, his post is excellent and may be more suited to your own natural inclination.
What does this "excess tension/headache thing" feel like? I know that sounds a bit daft but I'm interested to know what you're experiencing when this happens as I think I understand what you're talking about. The difference between samatha jhanas and vipassana jhanas is something I'm afraid I don't have enough technical knowledge of to answer, but my experience is that both practices, insight and/or concentration, will lead to jhana. The difference is that when you're doing pure concentration, you're solidifying these states whereas with insight you're observing these same sensations as being impermanent, unsatisfactory and not-self.
But a lot of that is probably lost time because I'm often either scattered or overfocused.
One advantage of noting which, in my opinion, might be beneficial to you is that, when done correctly, it's impossible to be caught up in daydreaming, wandering thoughts or any other psychological junk which may rear it's head because you're noting these mind states, objectifying them and seeing that they can't be a self. What do you mean by "overfocused"?
I tried it a little bit last night and had a pretty profound experience with it within a few minutes.
If you've crossed the 4th ñana, A&P, then your sittings will begin here as you cycle through up to the 11th ñana, Equanimity, and back down again. Take this as a good sign, it's confirming that you have indeed cross the Arising & Passing Away which means you're on the ride and that Fruition is more likely to be just over the horizon of Equanimity if you keep practicing well.
Today I was more tense and 40 minutes didn't do much (with at least how I was trying it so far).
You
might be meditating yourself into Dark Night territory and getting stuck there due to the inconsistency of your practice.
This tends to happen with me and techniques -- great initial success then diminishing returns and increasing tension.
I hear ya, I was the same myself for a while until I realized that this increasing tension, feeling that "this just isn't working anymore" and general aversion to formal practice are screamingly loud signs that you're actually making progress! Stick with this, pay attention to the emotions, the physical sensations, the mind states, and any other sensations which appear to perception. They're where the good stuff is and where that insight you're looking for will be found. See them as being impermanent, causing suffering and being devoid of self.
Lately I have been sitting at the local Zendo and just kind of sitting and relaxing. Sometimes this works great; other times it ends up "just sitting and thinking about the errands I have to run later and the conversation I had this morning and...."
What does it work great for? Sitting and relaxing doesn't bring wisdom, be accurately aware of what's appearing to awareness. As for getting distracted with daily life thoughts, it's no big deal but just bring awareness to this moment and not to what's gone on in the past, or might happen in the future. None of that exists, there is only this moment.
Hmm, where would I post something like that?
Here's some of my own practice threads,
[1],
[2],
[3],
[4] just post wherever seems most appropriate to you.
Hope that's of some use to you!