Network response time is one of the important factors that can affect SharePoint farm design. Ideally, you need to measure the latency between SharePoint servers and users in order to reorganize servers according the smallest response time.
Network latency is the key point to determine which of the proposed scenarios to implement in the current SharePoint deployment. (Latency is the time required for a packet to travel from one point on a network to another).
Analyse the existing infrastructure and plan a SharePoint topology for redundancy.There are several different topologies - from three to six servers in farm, which can be used as a baseline. Which one to choose depends on the level of redundancy and available hardware. Not all clients can afford topology with six or ten servers in farm due to budget limitation or data centre capabilities. Finding the compromise between numbers of servers, type of hosting and servers’ roles become critical task, because this choice will affect performance and extensibility of the SharePoint farm for several years ahead.
Plan number of site collections and sub sites in advance - content, location, security. Start with the single site collections and several sub sites rather then creating several site collections, and try to avoid new site collection if there are no requirements for this. The reason of such structure is that each new site collection works as a new application, with isolated scope to features, templates and search. Maintaining such structure is much easier than several site collections.
Do not end up with one big content database, because data optimisation will cause troubles in this case. For the small and development environments, single content database might be a preferable choice. However, for the large farms create several content databases and organize site collections among them. Having several content databases with sites helps to address the following: