I am new to competitive programming, I started solving the questions from the easy sections(From maximum number of submissions). I solved some of the questions but I always get stuck into the problems of grid walking, I always end up giving up on them. How do I get familiar with such problems.
And please refer me to some good and basic problems on grid walking, and also some source to form the base to solve such problems.
Thanks in advance.
This will give you basic idea of grid floodfill algorithm.
Solve these problems on SPOJ
Now proceed as per your wish. You can explore more algorithms and practice more harder questions
EDIT:
More problems:
sole these 
and get some good tutorials on topcoder
Happy coding:)
Here is a blog specifically for problems based on grids !
Problems :
Most of the problems involving grids are either dynamic programming problems or are based on graphs(BFS, DFS, shortest paths, minimum spanning trees etc). Just search for these tags for more problems on codechef,codeforces,spoj .
is it good to solve questions from maximum no, if submissions.
Yes …
Yes… Its absolutely good. Solving easy problems first helps to build up your morale.
Thanks, buddy.