Graduate school gives you a chance to learn about a subject in great depth, in an environment where learning is valued. You will have the opportunity to develop your ideas and to contribute original research. But grad school is a lot of work and requires strong motivation and focus.
Many of the difficulties people experience in grad school are related to the unstructured nature of these 4+ years. At LPL you'll fill up your first two or three years with classes and exams, which are very similar to most people's college experiences. There are assignments, deadlines, and guidelines for passing. When you begin doing research, however, it is not uncommon to feel lost or unmotivated, as seemingly endless stretches of road lie ahead. Frustration, failures, and burnout are frequently encountered. Interspersed with these are periods of exhilaration, when you may get a brilliant idea or have a wildly productive week. The key is to realize that you are NOT alone; the personal and professional tragedies, aggravations, depressions, and triumphs you go through in grad school are part of the process and are shared with everyone who goes through it.
Balancing a personal life with the intense work of grad school is not always easy, especially if you are raising a family. Be sure to take time out from research for yourself. This not only keeps you more or less sane, but often your brain will pop out ideas when you least expect it. Try to keep a regular schedule. Weekly tennis lessons or pottery classes keep you from drifting aimlessly day to day, and a regular sleeping and eating schedule will keep your body feeling fine. Time management skills are critical to a productive career here. Set realistic deadlines for yourself and stick to them. Above all, talk to other grad students!! Often your fears and problems can seem insurmountable, but we've been there too. Other people have strategies that may work for you or know of resources you can tap.
Many people recommend keeping a notebook. Jot your ideas down as they strike you so that you can follow up on them. If you've been having writers block and the perfect sentence forms in your brain, write it down before you forget it in a place you can find it! If you come to a roadblock, note it and what led up to it so that you can avoid it in the future--and if you find a way around it keep track of that too. Write down citations to useful papers. Even take it to talks so that when you vaguely remember something someone said once in some talk, you'll have a reference. Nobody's going to look at your notebooks, so keep any ideas in them, no matter how half-formed, speculative, or random (the exception is the working lab notebook, which, of course, should be well-documented).
One of the most important things to do while you're here in grad school is to establish yourself as part of the research community. Make yourself visible by attending conferences, publishing research results, collaborating on joint publications, meeting and maintaining contact with colleagues, and promoting your own work. The key, however, is to go about this carefully, so that you come across as intelligent and capable, not loud and superficial. Your assets in this quest are your own brain, the Lab itself, and the numerous conference and travel opportunities available.