Everything you need to know about buying a bespoke suit
Indeed a lot of couples think that the choice of a bespoke suite for the groom is much more easy than the choice of the wedding dress for the bride but we would suggest some argument here.
The best way is to buy a traditional English or Italian tailored suit from materials of good quality.  
As for a classical English style the suit jacket has flap pockets and features a double vent for ease of movement. The lapels are a thin notch or peak with a fair amount of padding in the shoulders to make the man look sturdier. The focus of the jacket is on the chest where the gorge lines sit over a fair amount of cloth or interlining canvas. The armhole is placed higher so that the jacket does not sag. Finally, the trouser also has a slimmer cut that lengthens the leg and guides the viewer’s eye upward to the wearer’s face. The English style pant is pleated inward and worn above the waist.

The Italian one is the exact opposite of the British suit described as rigorous, concerned and conservative. Italian tailored suites has two pieces instead of three, thin fabrics made to facilitate movement.
As for must-have #1.
We kindly recommend for the groom and his best men to wear a bow because it is ageless fashion – always better to get it than not.
One more important issue is the colour. The following colours should be chosen carefully:
Р    Vibrant colours such as red, blue, terracotta
All of them deflect attention from the bride and decoration

Р   White, nude, ivory
Very difficult colours to mix and match because they side with bride’s dress

Where to buy?
High price
1. Kiton
2. Cesare Attolini
3. Brioni
4. D’Avenza
5. Isaia
6. Sartorio Napoli
7. Tom Ford
8. Ermenegildo Zegna
9. Feru
10. Uomo Colezzioni
11. Hugo Boss
12. Canali
13. Garrison
Less price
1. Suitsupply
2. Mr. Start
3. Albione
4. Asos
5. Cacharel