How are you applying the Tru-Oil?
The method I use was shown to me by a gunsmith a long time ago and he had been using it for much longer than that.
You will need the body or neck sanded to where you want it.
Tack cloth
Jersey cloth (t-shirt material) preferably new stuff rather than an old t-shirt as it will have more body.
Tru-Oil.
XXXX Grade Steel Wool.
After sanding I use a tack cloth to remove dust, then get a damp cloth and rub over the sanded surface. This will make loose wood fibres stand up.
These are then sanded off and a tack cloth used again.
Now using a folded square of jersey (t-shirt material) place it over the neck of the T/O bottle and briefly invert the bottle to get a small amount on the cloth.
Start to rub the oil onto the a small patch of the timber in a swirling motion, keep going until you feel resistance. The T/O will sort of get slightly tacky.
Put some more T/O on the cloth and do the same for an adjacent area. Try not to overlap too much.
Repeat until the whole area is covered. Hang the body or neck in a dust free place and leave it alone for a few days. Now take the used cloth and submerge it in a bucket of water and leave it there. Tru-Oil soaked cloth has been known to spontaneously combust - I've never seen but I know people who have.
Do a second and third coat in the same manner.
Lightly rub with the XXXX steel wool. Wipe down and run over with the tack cloth to catch and bits and any steel wool fibres.
Do your fourth coat. Now you can probably start applying coats a bit more often even six or eight hours apart if it is not cold or if it is very low humidity.
Keep applying coats until you are happy with the finish. Every four or five coats knock it back with a very light going over with the steel wool.
I have done well over 30 coats on rifle stocks.
By the way, leave the usd cloths in the water for a couple of days then dry them out in the sun before turfing them out.
Now here is something that a lot of guitar forums seem to miss about Tru-Oil. It is a rifle stock coating. Which means it is hardy and resilient to water, grime and sweat. As a rifle stock coating it is not really designed to be glossy and slippery, Satin-Gloss with grip is probably what it is best described as.
It is not a guitar coating which means super slippery and glossy it ain't.
Don't rush it, enjoy the cathartic release of sitting in the man-cave rubbing your wood. Patience is the secret.