It never asks to hurt to ask the people who are right in front of you, lol.
My question is: I am unfamiliar with the worship of many gods and, especially, goddesses. What do you do? Do you just pick a god and worship that one for.. ever? Or would you pray to whatever god that could aid you the most in a situation? Or both???
If you wanted wisdom, would you pray to Athena, and then, if you wanted to be desirable (say for a date or party), you'd pray to Eros/Cupid or Aphrodite/Venus?? Is it alright to switch from Greek to Egyptian to Roman? Does anybody pray to any of the Hindu gods, Bhuda, or the Christian god?
I've gone from believing the the Christian god, to The Universe/Forces, and now I'm curious about "the gods". As you can tell, I'm still at just the beginning of my spiritual journey.
I know there's no "Jump-start Pack" for any religion, but can you give me some sort of insight on what ya'll, more experienced folk, do?
All words are appreciated!

Hmm...well, it really depends on your beliefs, practices etc and who you're asking.
For myself, I am a hard polytheist. I believe that the gods are all unique individual entities that deserve to be treated with respect. I specifically worship the Hellenic gods, and have a more reconstructionist (though not entirely so) approach. I rarely ask the gods for anything, other than asking the three gods whom I worship particularly closely for guidance...other than that, there are several goddesses that I worship but never ask anything of, they really ask nothing of me, but I do freely give them my worship from time to time.
This means:
1. I cannot just pray to "the lord" and "the lady" and know that they will pick the right gift from their bag of blessings and send me what I need cause they know all or something like that.
2. I cannot just pick some name from a book and ask that name for the gift of whatever blessing I'm looking for because it's all the same and they're all just different names of the same being.
3. I cannot "use" the gods.
4. I cannot just ask the gods for every little thing that I want that comes to mind. I don't really think Eros would like it too much if I asked him to help me be desireable every time I went to a party or on a date.
(Personally, I find points 2 and 3 to be particularly offensive.)
So....basically, from my point of view, you need to establish relationships with the gods. I don't mean that you have to have devoted three years of your life to Aphrodite before you can ask her for some help with matters of love...but you wouldn't just run up to a stranger on the street and ask them to help you find a date, would you? Much the same thing. So you take some time, learn a bit about the deity in question, meditate on them a bit, say a prayer or two, basically...introduce yourself.
This need not take a particularly long time, but over the course of a few days or so, spend some time paying attention to them first.
Once you establish a relationship with a deity, you can keep that line open. It doesn't have to be a strong, intense devotion- it very likely will not be in fact. But making an occasional offering "just because" and spending a bit of time every now and then meditating on a particular deity, it helps to keep the relationship...and if you find that you're especially interested in a specific deity with whom you'd like to develop a more regular relationship, or if you find that you're getting a lot of help from one in particular, then you might want to look into putting together an altar or shrine in their honor...but this seems like it might be wandering a bit beyond the scope of your question.
As far as mixing jumping between pantheons, it depends on your religion. If you're strictly neopagan, then it probably doesn't matter so much, except as far as it matters to you. If you're looking at practicing a reconstructive religion (Hellenic recon, Religio Romano, Asatru etc) then it depends on the culture and context and often you will find that it's not a big deal in reconstruction to worship deities outside of a pantheon, but what's important is that you worship them in their cultural context- you might worship Zeus in a traditional Greek manner and Njord separately, in Norse fashion. (It's not uncommon to find for example a Hellenic recon who worships a deity or two from another pantheon)
That's my take on things.