Newb Warrior needs some knowledge.
well i just wanted to start by saying welcome to the warrior master race.
based on what you have said this is a pretty basic warrior build using the weapons you have listed. http://gw2skills.net/editor/?fIAQNAneRjcOxwtQCPMxBAkirq6oQJmUPmzt4A-jUCBYLCi0yAEIgUBQJQFRjtSqIas6FYqSER1eDFRrGA-w
as a warrior you should make sure to key bind your weapon swap to something within comfortable reach because you are going to be using it a lot. up close the sigil of hydromancy pretty much guarantees that the shield bash will land which will of course mean your eviscerate will always crit if you chain it right.
here is another build that might actually be a little overpowered. http://gw2skills.net/editor/?fIAQNAT8ejkOxwtQCPMRCC8BscekkpQe9h5kKcGA-jkyAINBZqSgpOQ5xioxWNLiGrmBTbCoWXUtDJYelFVDA-w again the weapon swapping is important and will help you to stay alive and maintain pressure on your opponents.
the first build is amazing in dungeons and has a lot of spike damage in WvW. but its also a do or die build for WvW so if you don’t win the fight quickly then its easy for you to get kited to death.
the second build is pretty good for small group and solo roaming in WvW. its a lot less fustrating then the first if you plan on doing WvW a lot on your warrior.
Mesmer should be easy for you. All you have to do is keep pressure on the real one. On the eng part odly enough i found my condi build way more affective the a burst build.
Try Skull Cracker.
Most roaming Mesmers run Zerker armor Shatter builds. Block or dodge Mind Wrack, then stun lock them, keep the pressure on the real one when they Blink or Phase Retreat away. They’ll go down fast if you can get the hits in.
Engineers are more tricky, especially the ones running full Rabid condition damage builds with lots of escapes. Not sure what to advise about those, other than the general rule for warriors – keep the pressure on hard.