Well first off, welcome to FT and also to that same conundrum we all once had and most would never admit...
With airlines, at least, it’s having miles in too many programs you have been flying on for work stuff cuz your company thinks in terms of short money and not long-term results (hehehe - sorry, mine did too once)
Annnnyway,
I'd say to start out getting the credit card(s) that offer bonus sign ups on airlines you think you will use the most that go to destinations you want from where you live with the greatest ease. For example, United does not get me from BOS to NYC but AA does. hence, I applied for and received the AA Mastercard and I use it religiously.
There is a great threads on the visa United credit card sign up right here on the main page and also the thread on this pretty neat citibank 10k AA bonus. Couple that with a AAdvantage credit card, which offers 20k miles on sign up (see the top of their main page at
www.citicard.com) and you have nearly enough for a RT econ ticket from an east coast city to the islands of the Caribbean! (you need 35k for this so 20+10 + what you may already have could do it!)
You gotta track everything, print out stuff that's pending so you are sure to get your miles when waiting on promotions that sometimes take time to come thru (the above 10k offer takes like 3 months and the credit card postings for initial bonus are at least 4-6 weeks before you receive miles)
I'd try to stay with one or two--mayyyyyybe three airlines and learn about the partnerships too. Example: if you have us and ua miles, note that you can fly on both airlines and post all miles on ONE. (Again, be sure to print and keep everything including boarding cards and even luggage tags because more times than not, someone forgets to post your miles to the partner airline and you gotta fax in stuff and wait for them to fix it). I keep little files on my mileage activity and can toss them when everything finally posts if I need do.
Sign up for things like dining for miles and online shopping where ever you can (I use Best Buy to buy ink for my printer and I get bonus points at NW airlines and even if want to get things in their stores, one can purchase online and direct the products to be waiting at a nearby store for pick up) I have bought Home Depot gift cards of huge $ amounts to be shipped to my home within days because AA had offers for double miles when buying from them online thru their shopping portal, and then I would go to the store and buy whatever I needed anyway since I am doing tons of home improvement.
Lastly (for now), try to get all accounts to an even number amount... example: If you can, somehow do some of the above stuff to get an account that has say 24,443 miles in it up to 25k even if you may not be using it right away. This is so when you do need to use it, you don’t have to plead with an often ‘harsh’ customer service rep to expedite some missing 600 miles you expected from something you thought would post on time but never did. Same goes for lesser accounts... One never knows when having 10k miles in an airline could be useful... Some airline web sites even allow transfer of miles from members and even if the fees seem high to some to do this, you may have a friend who is willing to do it with you and in return, he or she may book u that ticket to Miami on an airline account that they never use but didn’t want to let go by the wayside. If that person needed your 10k but all you had was say 8,850, then this would not help anyone. Bring those accounts up to whole numbers if you can. having friends willing to do mile stuff with ya is beneficial. Leverage this where possible.
Hotels: Stick with Starwood and maybe sign up for the AMEX SPG card now too. Hands down. Let the others flutter in the wind, I'd say. (but that's maybe just me) Hilton, of course, can be good for some people because if you sign up for mypoints.com, you can transfer points to them for hotel points. They suck tho because they said they never received my last few transfers even though I have printed records of these and so they closed my Hilton account due to too much time of inactivity. I am still battling with them as we speak but I will win because I have printed proof of my mypoints transfers to the hotel awards program. (Oooo that Paris chic is gonna hear from me! hehehe)
I'd start by concentrating on newbie mile management 101 and then in the meantime, get those credit cards and charge EVERYTHING! (just pay 'em off every month on time and in full too, eh?)
Good luck, mate!

MM