Shaman are much more viable now then they were in TBC so if you did decently then you should do well now. You have to play a little bit differently though. One mistake and you can get blown the fuck up by almost any class right now so you kind of have to play on the safe side rather than over extending yourself. We do have a lot more tools at our disposal which take a bit of getting used to. You don't really have to worry about your gcd usage when it comes time to interrupt because of windshock off the GCD. Hex is nice but it's different then most cc in that the person can still drop totems, spell reflect, bandage, drink and
move while under it's effects (there are probably other things you can do as well that I just don't know about).
As for glyphs: The LHW wave is an obvious choice, it's pretty amazing. I really like the Flame Shock glyph, it's nice in that you can use it against rogues and force them to burn clos to vanish and you can use it on whoever your focus target is a bit before you plan to unload and you can have an auto crit lvb while still having your shock for an interrupt. That just takes some planning. For the third glyph a lot of people go with the WS glyph which is pretty decent I suppose but depending on your comp it can be unnecessary. The healing wave glyph is nice to have against warlocks and shadow priests(lol) but other than that kind of meh. I personally use the water shield as my third.
Specs: I change my spec around a lot but keep in mind that some of my choices deviate from the comp that I primarily play (it's resto/disc/retribution paladin right now; I don't really play much of anything besides 3s). My current spec of choice is along these lines:
WorldofWarcraft.com -> Info -> Classes -> Shaman -> Talent Calculator
Sometimes I switch some of the points out of Tidal Mastery or Guardian Totems into Elemental Shields depending on how I feel. With the comp I play there is virtually no point into speccing into Healing Grace since discipline priests provide a ton of dispel resistance. I find mana tide pretty necessary to have (with some coordination from your team mates+protecting it with stoneclaw I normally get the entire thing and in our type of comp it can make or break games). Your spec is really going to change depending on what comp you play. The rest of the stuff is pretty standard, there isn't a whole lot of deviation between resto specs in general.
If there is one piece of advice I could give you (this applies to anyone and everyone, not just resto shaman) is to be careful who you queue against. With the way your hidden rating works if there are not a lot of teams queueing and with how bursty the game is right now it isn't too rare to randomly lose one out of 5 games to a team much farther below you. Just this week my team went 14-5 and we went
down in points because there was only one RMP queueing and they were terrible, we would beat them 5 out of 6 times and get 3-4 points each time and then they would RNG someone down and we would lose 16. If you are queueing only against one team that you are getting no points from
stop queueing! You are going to get unlucky and lose 45 minutes of work. On the other hand if you are queueing against someone much higher above you, even if you are getting stomped every time, you may as well keep queueing. You may lose 2-3 points every game but if you get lucky in one out of 5 games and steal 20 points from them it is still a net gain. And with how quick paced these games are right now, it's not hard to get lucky.