You need to collect the appropriate (sewage, fecal material or clinical) samples, depending on the which phage you are targeting and their respective host habitat. Once you get the good number of samples, the samples needs to be centrifuged and treated with chloroform to kill the bacterial contaminants. The processed samples subjected for co-culturing with the host bacteria to enrich the existing phage population.
Careful with the chloroform, for reasons I don't understand completely it is lethal to some phage. We learned this once the hard way... Filtration might be safer.
Some people treat soil samples with potassium citrate to release more particles. see: https://aem.asm.org/content/69/11/6628.short
Be wary, every phage-host system has it's own way of operating. Don't be afraid to change things up a bit... depending on what you are looking for.
What are the possible ways to increase the size of palques. Initially have used basal media. It was followed by use of LB with 0.6% agar. Can anyone provide with suggestions that can give me a bigger plaque size.