If you have some upcoming stays with Marriott, you may be able to take advantage of their status challenge. It is open to people who don't already have status with Marriott (Silver is okay), have status with one of the other hotel programs, and have completed at least one stay with that program over the past 12 months. As soon as they approve your application, you'll have corresponding status (usually Marriott Platinum) and can enjoy the benefits on any upcoming stays.
Normally, you'd need to spend 8 nights in 90 days to lock-in Gold status and 16 nights in 90 days to stay qualified for the much more valuable Platinum status. But for the current promotion, they've dropped it to 5 and 15 nights respectively. Status Match Webpage.
You can earn up to 30 elite night credits each year with Marriott credit cards (without any spending requirement). This drops the requirement from 50 nights to 20 nights and brings Platinum status into the reach of many more people. You'll earn 15 elite night credits if you have one of the Marriott personal credit cards and an additional 15 elite night credits if you have one of the business cards (you can't earn additional credits by having multiple different personal or business cards).
Each Marriott card also gives you either automatic Silver or Gold status, but this doesn't provide that much in the way of benefits. Silver only entitles you to the potential for late checkout and 10% bonus points on stays. Gold bumps the bonus points to 25% and gives you a small points boost on each stay, enhanced internet access, and the possibility of an upgrade to a slightly better room. Spending $35,000 per year on one of the cards that normally gives you Silver status will bump your status to Gold, but this is almost certainly a bad idea.
United Gold elites can also be matched to Marriott Gold status. But no level of United status is good enough for Marriott Platinum. Register Here.
You can also earn Platinum status (without any stays) by spending $75,000 in a year with the Brilliant or Ritz Carlton cards. Obviously that's a lot of money, but if you aren't going to spend at least 20 nights, it may be your only option for Platinum. At a 1% opportunity cost, it would "cost" about $750 to earn Platinum status for up to two years. While the Brilliant card has a high annual fee, it is offset by a $300 credit you can use for stays and a free night certificate (good at hotels at up to 50,000 per night).
