Recently and in the past I have been practicing writing as a hobby. I enjoy the creative pleasure it provides, but am hitting major road blocks in the process. My trouble is in seeing the big picture. In college I studied math and physics, and am very good at analyzing, but have enormous difficulties when it comes to creating something. Whenever I write, the material always comes out as a sequence or list. I usually end up listing attributes of a character, events, or details of the setting. I can't seem to tie these things together and make a real story. I feel like every sentence I write is disconnected from the rest. What exercises can I do to improve in this aspect?
There is nothing wrong with writing like that in first draft. Get events in order, write down attributes, reasons, settings, in a way that is comfortable for you. Have all the essentials in an easily accessible order.
Then perform major editing.
First, show, don't tell. Look at every single attribute you list and think how you could replace it with a segment of text that shows it. In many cases it would be forced, so skip these, but in a lot of cases instead of just telling the reader something is this-and-this, have someone ask a question about it, have it perform a role in the plot, imply it through effects, change an attribute to an actor.
Cut. Delay exposure of things that are not essential now. Mix order - events, descriptions, dialogues, no clear separation 'here I introduce the setting, here - characters, and here I have them interacting' but put it in one flow, mixing these. Chop into finer pieces and mix together.
Next, Camera work. When writing descriptions, think in terms of moving camera (or eye focus), and instead of just setting the camera on a tripod and dumping the static image it has within view frame, pan it, zoom in, zoom out, turn around, wander, make a double-take at something that at first seemed normal, but appeared out of place. Currently, you imagine a scene and describe it point by point, in some specific order. Instead, just think how to move the camera around, zoom in on important aspects, or opposite, zoom out from a detail into vista, for large image. Your list is an excellent help in getting what is to be shown, but transform it into a story.
Always think in three layers.
Every moment of action is a result of these three, and always have them in mind. You can always remix them - emotions showing up as facial expressions, cold logic coming as determination or just displayed in smart actions, observations of real world reflected through emotions - but keep all three in the flow. If you spend a whole page only displaying real events and never peeking into the thoughts and emotions of your characters, your writing gets dry. If you spend half a page on dwelling just on internal thoughts of a character, your readers start yawning. Mix these up.
Continuity. While 'cut' was on microscale, mixing most immediate elements, also break continuity on macroscale. Start later into the story and bring the beginning through reminiscences. Disassociate the reader from the place - observe the story through TV news, tell it by grandpa's mouth, have a character brag about past endeavors. Change scenes, skip through time, don't just list events in original order but keep parts a mystery to be revealed later, or even just guessed by the reader.
Pacing. Some events require deep detail, time grinding almost to a halt, others span a long time and require a fast-forward view. Similarly to camera works though, change of pacing should be smooth. Events follow at certain pace, and you must use smooth transitions if the pace changes (outside of chapter/section breaks). Speed up or slow down gradually, see this answer for an example. There is a wide range of paces - Genesis in the Bible has whole generations pass within single paragraphs, meanwhile Tom Clancy has a sizable chapter in his Sum of All Fears, that spans under a microsecond of real time. Still, unless you break a scene or a chapter, if you do speed up or slow down the pace, do this gradually.
In addition to SF's excellent advice for the nuts and bolts of writing, if you're having difficulty coming up with a skeleton to hang your story on:
1) For a tried-and-true classic, try the Hero's Journey. (Star Wars is the perfect contemporary example.) Something happens, person goes on quest to fix it, gets help and hindrance along the way, is successful, returns home. Christopher Vogler wrote an excellent, step-by-step tutorial on creating these stories, called The Writer's Journey.
2) If your story doesn't fall into that structure (and it certainly doesn't have to), I found Randy Ingermanson's Snowflake Method of plotting to be really useful.
You start with your plot as one sentence. Then you expand to one paragraph. Then to a page. Then you start blocking out acts (he calls this "three disasters and an ending, if I recall correctly). Basically the structure helps you to expand your story naturally, filling in the details where it's important to have them.
There are other methods, but these two are well-proven and can help you to join up your bullet lists into an actual plot.