Insufficient Travel History If you have not had sufficient international travel experience to Western countries, your chances of obtaining a UK visit visa on your first attempt decrease.
You Can Apply Well in Advance You can apply for your UK visit visa up to 3 months in advance. Most people wait till the last few weeks, but applying early allows you to reapply in case of rejections.
Processing Times Are Not Consistent Though a UK visitor visa usually comes through in 15 days, sometimes, the visa can take up to a month to come through. So, ensure you apply in advance.
Cannot extend a Standard UK Visit Visa If you are in the UK on a standard UK visit visa and want to extend your visa period, you cannot do that. You will have to leave and reapply to come back.