Read this. U may get it for free.
Short straddle :
What is ?? Sell an atm call and put.
Instrument: mostly bnf and nf.
Now there are versions of it.
1. Best version :
Enter around 9.15-20 and exit around 3.20. No adjustment nothing.
1/n.

If u r doing it on zero leverage(meaning u have full capital of around bnf's notional contract,i.e. 40000*25 = 10lacs), then u r most likely going to make better than fd or anything like that.
Simple rules : friday,monday, tuesday do for weekly. Wednesday and thrusday next week

So, gamma moves can't impact much.
Another better version of mahesh chander kaushik is to do it for monthly expiry.
Bigger premiums and never hav to worry about 200-300 points sudden moves.
2. 2nd version : have combined stoploss of premiums and re-entry criteria. Example :

Let say 40000 straddle is at 600. Sell at 600 and hav combined sl at 650. Many algos are providing this. U can even place stoploss in % terms. Like, if sold straddle at 400 and placed 10% sl, means if 440 combined premium touch, it will be stoploss.
Let say, in morning,

U sold straddle at 600 and it sl hit at 650. Now, u placed reentry at 600 with same sl. This time may be linear decay happens and u may cover morning's loss and make some profit.
3rd version : stoplosses at each leg and trail sl to cost type.
Example , 40000 straddle at 400.