it depends if you have a slow internet connection or an old computer, or both
If you think its just slow internet, then theres really just nothing you can do, maybe just reset your Modem, or router if you have one.
If its a slow cp then I have many solutions, here are a few:
defrag it, follow these steps (unless you know how to do it
>>Start Menu
>> All programs
>> Acessories
>> System tools
>> Disk defragmenter
( you can also do just Disck cleanup, its much quicker)
The defrag takes a few hours to do
another solution is to update your cp. I dont know if you have Vista, Mac, Or WIndows, but the update thing can usually be found somewhere in the start menu
Something ive used recently that has really helped: ccleaner
ccleaner is almost just like disk cleanup, except it cleans EVERYTHING!
visit this site: ccleaner.com
>> Download ccleaner now
ignore all the paypal stuff, you can just get all this for free
>>download from filehippo
>> go from there
I hope this was helpful, I have alot of lag too, but all this has helped me, I hope it can help you too