I usually wind those long faux fir garlands round , they have wire in them which forms a hook at the end.
Had to be ruthless with the decorations last year , some past their best.
So this year I'm planning:
we have straight upright wooden strutts (cream) and some small glass tea-light holder baubles. I'll get some LED tealights, fishing wire (invisible ) and tie round the bannister, bit of Blu-tack then a fancy ribbon spiralled round to hide the tied bits.
Maybe ivy from the garden at the end post .
The DC are older now so glass not an issue.
In years gone by I've collected tiny teddy bears and tucked one in the corner of every step (stole the Teddy on every step idea from an article about a child friendly hotel) 
What are you planning, inspire me .