Gringo has linked to a suspension seat post, which is possibly the best way to gain comfort from a hardtail.
A few things.
If you haven't already done so, here is a set up guide for the front forks.
http://www.srsuntour-cycling.com/fileadmin/user_upload/Downloads/Consumer/Bike/Owners manuals/2014/general-fork-manual-english-web.pdf
if you don't already have one, then buy a shock pump in order to set the front suspension up and set the static sag. Start with approximately 20-25 per cent of the travel- so, if your fork has 100mm of travel, it should compress by 20-25mm. Be sure to set the sag wearing your full riding kit, including water that you may carry.
I'd also remove the suspension lockout, but that is just me.
In respect of tyre, the consensus of opinion suggests that fork and bike quality aside, tyres are a very crucial aspect of hardtail set up.
If I am correct then your bike is currently running 2.25", which mine is as well, but all that I have read, suggests that 2.3 is a minimum starting point width. I don't have any issue running 2.25" so clearly that isn't always the case.
Tyre pressures are very critical though and as starting point, aim for 28psi in the front and 30psi in the rear - adjusting upwards by a couple of psi if you are above 75kg in weight, or down if you are less than 75kg. Equally, bigger volume tyres can be run slightly softer than narrower ones. Either way, too hard and they will be harsh and offer little grip; too soft and you will be more prone to pinch flats and rolling the tyre off the rim.
Optimise your riding position. There must be loads of Youtube advice on this one, so I'll leave it there.
Hardtails are also best ridden using a clipless set up, so if you aren't already doing this, think about giving it a try.
In conflict with Gringos take on things, which as said, is going to be the best way to gain comfort; if you are riding off road a lot, then you might want to think about the following.
With no rear suspension, your legs have to absorb the bumps, and dropping the seat down to help them get their full range is going to help all round. A dropper seat post is another item that you might perhaps consider fitting. Having said World level XC mtb racers don't seem worry about dropper seat posts. :0
Riding terrain should also be taken into consideration. Hardtails are better suited for longer distances over slacker gradients and smoother trails. Not that I really give thought to this, as I tend to ride anywhere that I would on the Full suspension Lycan, and don't give it too much thought.
I have made two changes just today though, in respect of comfort.
I have fitted a Ragley Tracker saddle, and a pair of Ritchey WCS True Grip foam grips.
The Ragley was chosen after reading many reviews, and the True Grips were chosen on the basis that if they are good enough to be used by Jenny Rissveds, then who am I to argue.
