I had a very long LD, probably about 10 minutes in dream time, and I tried numerous times to create objects out of thin air, in my pocket, under the table, in a backpack, and failed every time. It’d be great to get people’s techniques for creating this, so I could do it!
I think my problem may have been that I failed to visualize strongly what I wanted, although I think I tried imagining them and it didn’t work… iunno.
Try calling/yelling it out.
“I want a muffin!”
i was going to ask the same question because i was having trouble changing scenary and manipulating the dreams…
im having trouble staying asleep to once im lucid but im gettin better at it…
i have had SOME sucess with getting people to come into my dream. i was in my room and i simply told the person i wanted to see to get out of my bed and right away she came up from under my blanket. i made a voice command to see someone else and they came walking down a stair case…
i could use some help though too
Interesting. I haven’t purposely LD’d yet, so I don’t know how qualified I am to make a suggestion. But I read that creating things is one of the hardest things to do in an LD, and you need a fairly high level of lucidity. Different things work for different people though, at least usually in things like this. My advice would be to experiment and to keep going on your DJ, or if you haven’t started one, start one! They apparently help getting more lucid, DR, etc.
For objects, I usually try to make them just appear out of thin air. It usually doesn’t work for me, though, so I’m trying to get into the habit of using the pocket method. I used the pocket method once and it worked perfectly, so I think the trick is not to hope or expect it’s there, it’s to know.
For people, I’m still working on that. So far I’m using the “Oh, he/she/it’s always there” or “we arranged a meeting.” I want to try pulling people out of pockets sometime. 
I don’t change the scenery a lot, since I usually fly or swim there. You could always tell yourself “This place is right beyond that wall/mirror” and walk through the nearest wall/mirror. If what you want changed is something minor, try working on conjuring objects first, and pull out a magic potion/scroll/wand/ect. or something that could “assist” you with getting something done. 
as fante says. The secret is to have no doubt in your mind that it will be there. Just expect it to be there.
If you have the slightest doubt, it won’t work.
If i need something, i too usually use the pocket technique, or i look around for it, I will then find it somewhere.
Come to think of it I rarely search for items in a LD.
The yelling-thing did never work for me. I tried multiple times, to change things by just calling for the result. I yelled for my dream guide, shoutet “bright! blue! sunrise!” at the dark sky, and so on… nothing worked.
even worse, each time I tried this I awaked a frew moments after that. May be just bad luck and not related, but I’ll no longe try the yelling-technique, because it obviously doesn’t work for me and propably affects dream stability, too.
sucess!
I was walking into a room and REALLY wanted a specefic person to be behind the door. Walked in, there they were! I think what helped was that I had a mental image of them standing right there in front of me (because they were exactly where I imagined they would be).
It seems to me that what you expect to happen happens. Earlier in that dream I was going to my girlfriends house and since a lot of the time when I show up she is waiting for me in the front room on the computer, there she was on the computer in my LD! I think that she could have been a billion places but me expecting her to be there is why she was there.
Yaay well done 
… I’d have to go with the general concensus here, you just have to believe it will happen with no doubt on your mind. I eventually learned this with masses and masses of failed previous attempts, but all is well now 
Try the “pizza delivery” method. Get a phone (if you can’t then try talking into your hands). Tell whoever is on it what you want. In a LD i had, I needed an incense holder to light the incense i was given as a gift by a gnome character that I drew in RL. I picked up a pay phone, and a man said “this is Luke. How can I help you?” and I said “I need an incense holder.” and he hung up. A few moments later a seagull flew out of nowhere and dropped an incense holder in the hands of the gnome. Then I wrote this technique down in my notebook. I made it up completely, so I can’t say it works for everybody. I have a load of methods for doing just about anything, so if you need new ideas, PM or IM me. But this method works just about the best for me, so if you try it, tell me how it works for you.
Phones don’t work in my dreams. (No clue why, especially not cell phones.)
I would go with Q and fante and maybe just n00dle at the right times.
i have the same problem
say
i wanted my friend to appear
i would see a door and concentrate on having him appear on the other side of the door
ide open it and he wasnt there
so
i decided to say it
“my frend will be in the next room”
then i open the door again
and hes there
if i actually tell my mind with my dream mouth…
to do something… it happens
Oh it’s so nice to know I’m not the only one who’s struggling with making objects/people appear seems so easy when people describe it that I thought I was the only one who had problems with it lol.
I’ve tried yelling out for it several times and it barely seems to work for me. In my LDs I am aware that I have to expect it to be there and have no doubt about it, but how do you seriously expect a dragon to be in front of you all of a sudden? lol.
I think maybe the next time I have a LD I will think about what it really means to be dreaming, how everything I see is created by my mind and stuff like that… usually I’m like “yay I’m dreaming” but I never stop to think about what opportunities that brings.
In my last LD I also wanted to jump out a window, and for some reason I couldn’t get through the glass no matter how hard I tried. What is up with that? 