Check out Hui's Tailoring on youtube. Surprisingly helpful videos. Other than that, I learned a lot online. Most videos are made for women's clothing, but it's mostly applicable to menswear as well.
There are some good books on Amazon for tailoring and patternmaking if you want to move towards that.
Once you learn the terminology, google is pretty helpful for finding an article or tutorial.
I couldn't find my old posts (weird), but here's a progression. Do not jump to the next step until you can do a really good job at your current level.
I realize it may not be possible, but look for classes or seminars.
Man's cotton shirt with collarband, collar, tower sleeve placket, curved hem.
Man's trousers in wool.
Man's vest in wool and lining fabric.
Skills related to a man's jacket (double piped pocket samples, pocket flaps, vents, pad stitched lapel sample).
Jacket.
Books:
Reader's Digest Complete Guide to Sewing (general sewing)
Classic Tailoring Techniques for Men: A Construction Guide
Tailoring: The Classic Guide to Sewing the Perfect Jacket
Shirtmaking: Developing Skills for Fine Sewing
Online:
Mike Maldonado's shirt making videos and his video courses
The Cutter and Tailor forum (Read the section on how to teach yourself tailoring)
The Bespoke Cutter and Tailor forum (less strict than the forum above)
Rory Duffy's online videos (They are beautiful, but not in-depth enough to teach yourself).
The Notebook, a blog by Anderson & Sheppard, a Savile Row firm.
Made by Hand, a blog by Jeffery Diduch.
Classic Tailoring Techniques for Menswear. (The other books you see on the page may also be helpful.
http://www.needlesandknowhow.com/machine-sewing/altered-mens-suit-jacket/
/r/sewing
Pictures of the jacket and pants would really help us assess how much you need to do. The pants will be far easier because there is no lining. You would probably need to do undo the waistband, do waist darts above the middle of the back pockets, slim the pants by sewing on the side seam (reiron the crease, which will be out of line with this alteration). The jacket is going to be much harder because of the lining and fit.
The Reader's Digest Guide to Sewing is comprehensive; many people prefer the older editions. I'd also recommend:
Shirtmaking by David P. Coffin
Classic Tailoring Techniques for Menswear: A Construction Guide 2nd Edition http://www.amazon.com/Classic-Tailoring-Techniques-Menswear-Construction/dp/1628921706/ref=dp_ob_title_bk
Tailoring: The Classic Guide to Sewing the Perfect Jacket http://www.amazon.com/Tailoring-Classic-Sewing-Perfect-Jacket/dp/1589236092/ref=tmm_pap_swatch_0?_encoding=UTF8&qid=1459466582&sr=8-2
Learn how to use a sewing machine. Learn basic hand stitches. Buy a commercial trousers pattern and have someone fit it on you. Sew it over and over while you build up your skills.
Join the Cutter and Tailor forum. Read the rules carefully. You will only be able to post about shirts, vests, and trousers initially, but if you are serious there are many helpful people over there.