I really need to advance the Smith Skill Tree ,it's only @ lvl 25 ... i've never much used the smithing since most of the items (under lvl 30 smithing) could be found and bought...
But now i realise that i've been wrong :/ ... so pleeeese help me,i need to build up my smithing skills...what is the BEST way to do it? ... ALSO from which Smithing NPCs can i train/buy smithing perks (i've already trained all 5/5 novice perks from the smith in Rivenwood) any others?

I need/want to reach lvl 40-50 as quickly as possible.

Buy leathers and leather strips. Buy those as much as you can afford and make leather gauntlets, they cost only one leather and 2 strips, and they're a huge bump for your smithing... it's a money loss even after you sell the gauntlets but beats training fees by far

How about hunting? Free infinite leather.

you can also smith jewelery items and sell them for profit.

That, except I'm too lazy to run around hunting leather, leather is quite cheap that I rather buy them than hunt for them . For starting chars it's probably best to hunt but once you have enough money (if you have a house you have enough imo) you can just buy leathers, save time from all the running around

When ever I'm in town I buy all of the Iron ingots the blacksmith has and an equal number of leather straps and make that many Iron Daggers. It still raises my Smithing to fast.

1 - Go to the warmaiden in whiterun, buy Iron Ingots/Iron ore and leathers from the shopkeeper in or outside, press T and wait for 24 hours.
2 - Repeat step 1 untill you have around 300 Iron ingots/ore and 75 leathers
3 - use the tanning rack outside to convert leather to leather strips
4 - use the smelting to convert iron ores to ingots
5 - Craft 300 Iron daggers, and you'll gain around 70 skill points (and around 5 levels depending on what lvl you are)

This all costs around 4000 gold, and takes around 1 - 1 and a half hour to compleet.


* Also, save the daggers in your chest, there great for leveling enchanting later

Time is money.

Some very good tips guys I'll try both the Daggers and Lether Gloves

But no1 knows any other NPC that could train me in Smithing ? (apart from the Smith inRivenwood) cuz i got 20k gold ... so money is no pro.b

Why would you want to train smithing? the money it costs to lvl it past 40 is far more then it would cost you to buy iron ingots/leaters and craft your way up.