Actual LSD is rare to find, what you find on the market is another derivative to where they have to separate the bad chemicals out of it several times.. the more wired you feel and the more colors you see is mostly the side affects of those bad chemicals not being separated out good enough. That being said,-

Aside from the intensity of the trip, its all a state of mind. I have personally taken vary large amounts, so there is no need to allow your self to get paranoid about OD'ing on it. its all in your head.

Secondly do not do other drugs with LSD, your body may feel it but your mind wont, which makes it easy to overdose on other drugs while tripping. alcohol for instance, you can easily give your self alcohol poisoning because of over consumption because your mind is not feeling it.

if you do not feel your self tripping its likely not LSD, although if you had taken some then later take some more the second amount will have little affect, you have to give your self a few days to recoop before trying again or take a hell of a lot more of it which is a waste..

Edit: I used to be an LDS dealer back in the old Greatfuldead days. I ate it like candy, and knew people that took even a hell of a lot more of it then me. so I know a little of what I am talking about.