I experience this too. Sometimes it seems that it takes 30 minutes of a 45 minute period just to settle down a bit.
Some things that i think are helpful to me are, meditating first thing in the morning before my mind and body have been stirred up by events, food, noise, people and caffine.
If you cant sit first thing in the A.M. sitting at the same time every day, a few hours after you have had food or caffine, might be good, it seems to be of help to me anyway.
20 minutes or so of yoga before practice also seems to help in this regard.
Also sometimes i can make a sort of conscious agreement with the chattering, grasping, progress seeking part of my mind to just take a break and leave me alone for a few minutes till im done with practice.
If i can just surrender to being where im at and remember that this is MY path no matter what happens, or how fast it happens, this is also seems to help.
Grasping of course is non productive, but so is aversion, so i just try to happily co-exist with whatever thoughts i do have, as suzuki said "let them come in the front door and go out the back door, dont invite them for tea".
Thats all i got. I have been sitting on and off since the 90's since 08 or so more regularly. What i lack in talent i try to make up for in regularity
For me, effort, persistence and regularity are important, but just surrendering to the process is too imo.
EDIT: Just wanted to note that i do not do jhana practice, but another kind of concentration/absorption practice which results in (when im lucky