Something else I thought should be mentioned is that if your chest voice is not properly grounded or rooted firmly its going to show up as you try to get into the mix and those higher notes. That is something that has shown up a lot in my voice.

use your vocal fry to get into those higher notes. start extremely small, get a vocal fry going then gently and very lightly slide up into the highest position you can. once you can get those notes happening consistently work on adding a bit of solidness to them, swelling the volume.

I agree with everyone here! Though I will point out that do not confuse focus with strain. In my experience people (myself included) will think light way too much to the point where there is not enough focus on the note. If you don't put some real effort behind the notes you will get no where.

Sometimes those veins will appear sometimes it might be a little forced. It's alright to put your vocals to the test. Do it right and with reflection. Sometimes when I am trying to increase range or get a note to sound a certain way. I will just hit it anyway I can, but while I'm doing this, I will analyze the sensations.

Where was I focusing it on my palette, where in the mask was the note, how did my folds feel at that zipped position. After I have thought about it for a while (sometime a very long while). I attempt the note again but this time I hit the note and keep conscious of things like: breath support, am I pushing too much air through? Those high notes don't need a lot of air; Am I locking down the note with the power push? Remember though too much is just as bad; Am i spreading the note across the mask (note: this is different than spreading a vowel, which is bad.).

Something that is also very important drop that jaw! The more closed it is the more you are making that larynx work the distance. The larynx will raise to meet the jaw on higher notes bridge the gap and drop the jaw. Closing the jaw will hinder your ability to go higher.

Stand straight, siren up to the note (you may want to start in head.) and hold it for say 5 seconds. As Jens said it the note a few times a day. Also a good use of vibrato will take the stress off of the folds.

Sorry for the book. I have Judas Priest, Opeth, Dream Theater and Iron Maiden on shuffle. The awesome is flowing through my ears and into my fingertips! lol

Great answers guys, thanks!