96 corolla doesn't start well

standard, 145 000 kms on it. when starting it, have to crank it for close to 20 -30 seconds (happens mostly when car is cold). sometimes have to try 2-3 times before it starts. plugs are fairly new. Any hints on how I can fix that ?

Try to check :
Spark plug...(working & need to be dry)
gas/feul filter & Pump ...(dirty or not & gas quality..)
temperture....(mostly weather)
service all yours engine injector ...(get a good quality servicing work shop)
last one ,the engine oil ..... (you should know what weather to use the correct type )

Ps: either you use the wrong spark Plug , there are cold type for long distance drive or Hot type (check or ask the right person)