To try and get visuals going there are a couple things you can do. Stare at something (a vase of flowers, a poster, some piece of bric-a-brack, with a fixed gaze on a single spot for 30 seconds to a minute without moving your eyes around and blinking as little as possible.
This alone on just about ANY psychedelic almost always will have you seeing shimmering outlines, areas inside an outline suddenly brightening or dimming or changing color.
THEN... suddenly look away from the original thing over to a large blank wall, or if none is available, a blank white (or colored or even black but mostly BLANK) piece of paper or cardboard.
Now, the previous pertubations, as well as seeing an afterimage is a normal thing the visual system does even when straight, but a psychedelic, even weed but especially a proper strong psychedelic, will amplify these effects via its potent alteration of the neurons in the visual processing centers of the brain by MANY MANY times.... you will be very likely to see the afterimage, that would usually only last several seconds (and be the "opposite" colors as the original) last a VERY long time... consist of VERY strong exaggerated easy to notice color modulations, and also, this is the best part, its outline will often take on a life of its own and start to morph radically... sometimes randomly like jelly, other times into sharp, recognizable outlines of other related objects... like the outline of a house cat morphing into the outline of a lion, which may then stand up, grow legs and walk away. It seems that the tripping brain knows it is no longer seeing input from real objects that "ought" to remain constant, so the constraint of remaining stable is just ignored, and the freedom of alteration conferred by the psychedelic takes over, and the conscious awareness part of your tripping brain seems to understand that IT can now take control of the "outline shape controls" of this non-real afterimage projected onto blank paper and start to play with it at will.
Another EXCELLENT starting point is a field of repeated geometric designs, like those infinitely repeating arrays of starburst designs on a ceiling,,or those really cool arrays of little triangles in designs and patterns that they sometimes put into covers over radiators or walls and stuff... even a nice repeating wallpaper geometry design can work. Just stare at the middle of one of these for a while, and you will very likely start to notice strong and coordinated changes in color, brightness and darkness of the elements all around the point you are staring at, forming at first still, then maybe even moving outlines and patterns out of what is really a constant stable design, often to the beat and flow of the music if there is any.
Having MUSIC on during these exercises can often really help... while tripping there are MUCH stronger cross-influences between hearing and sight than normal... seriously, MUSIC, especially with a strong rhythm, can greatly enhance the formation of visuals.
NOW, and this is the key point: After you have done these "hallucination ignition exercises" for a while, this really seems to "teach" your brain/mind that "HEY! I can change what stuff looks like or make up whatever I want"... it can teach you how to SEE the visuals that your "must maintain visual stability" visual processing subroutines had been blocking.. and let you turn that subroutine OFF at will... you might then try closing your eyes to music and find to your delight that your mind has learned to create and project all sorts of things into the blank field inside your eyeballs.
When I first started tripping I too was disappointed and frustrated by the same "Wheres the hallucinations?" "issue". Then I just discovered by accident that I got more visuals staring at patterns, and doing the afterimage play thing, and learned that this could be used to jump-start the visual tripping processes that I had previously not really learned to notice or "turn on".
They call it "turning on" for a reason, and sometimes its just something you have to teach your brain how to do. Soon enough it will become easy and second-nature.
Hope this helps. Let us know if it does! (Does any of this ring a bell for anyone else?)