I worked for 6 or 7 years before going back to school. Here are my thoughts:

1. Start slow and easy. Take the easiest class you possibly can. Don't try the attitude of "let me get the hard stuff out of the way first." Because you have to relearn to study, commit time, etc. Starting off too difficult is a sure fire way of sabotaging yourself.
2. Use as many resources as possible. I'm always picking the brains of the professors, watching youtube vids, and looking up websites with info. Textbooks are horrible.
3. Rent all your books, unless there is one you think you can use specifically in your job as a reference tool. Chegg.com for example, is a popular one.
4. When starting a new class, do your first assignment early and have the instructor look at it before officially submitting it for your grade. All professors have their "quirks" about what they like to see, so getting their feedback on the first paper before you officially submit it will help you work out the bugs and ace the first, and all the rest of your papers in that class.
5. Most studies have proven "cramming" is ineffective. Students who don't cram, but get a better night's sleep often outperform those who cram and get a shitty night sleep.
6. If you have a big assignment, split it up into equal sections with due dates. Like, "All resources read by week one, rough draft by week 2, final draft by week 3, and presentation by week 4 to submit on week 5." Many times, assignments won't seem as large until you start doing them; which often time is when it's too late.

this man speaks the truth!! all the same shiz I learned in my psych class

Thank you very much for the advice everybody. It is all also a comfort to realize that many other people here have worked and then gone to school. And frost, thanks especially for number 4, it seems rather brilliant. On to doing placement tests. and wasabi for the look on the yellow ribbon. I always ask questions anyway, because I just always want to know more. If there is part that fails. I need to know why it failed. what to do to prevent said part from failing again. instead of just replacing the part.

Just don't procrastinate and you'll be fine.