EPTThe best way to start though is by playing against the AI. There is only one setting now, the very easy so that should be perfect for you.
Get to know the units, buildings and the general feel of the game.
Second thing you should do, is watch some videos and/or replays from SC2, you will learn a lot from it and especially the videos you can find here on TL.net or youtube.
You should then proceed to play 2v2, Free for all and only than 1v1. See what suites you best, maybe you can be really supportive in 2v2 matches, but lack the necessary stuff to succeed in 1v1. This is why its important to try out all the modes available in the SC2 beta.
After you do all these things, you should only than start to expand your knowledge about the strategies, counters, tactics, build times, etc... But don't approach it as a math lesson, aproach it casually and step by step.
Just use one simple strategy, mass some units and try to get something done, it you fail just shake up your strategy a bit in game and see how it goes.
Its important to say that you will be pitted against players of similar skill levels, you you won't have to have insane mechanical skills, great timings or the best build orders or unit combinations to beat someone.
Again, this is only a beta and there is little to none of tutorials, more AI settings, etc... The final SC2 game will have tutorial, mini campaign, co-op with an AI, mini skirmishes and stuff like that to introduce you to the game and introduce you to the basics or RTS and Starcraft 2 play.
There will also be the campaign, which you may enjoy even if you are not too fond on the multiplayer aspect of the game.
So overall it still depends on your preference. You could try it out now in the beta and judge, but again its only a beta, there are still lots of balance changes, bug fixes, content added and stuff like that.
Best thing would be to play the beta as I've stated, see if you have some fun and if you do, wait for the full game to come and and than play.
You will most certainly not regret for time "lost", since even if the campaign sucks, 1v1, 2v2, FFE, 4v4 suck, there will also be a lot of custom maps(games) like Dota is for WC3, tower defenses, RPG's, adventures and puzzle maps/games that you may actually get quite fond of.
